Search

Risks from human intervention in the climate system are raising concerns with respect to individual species and ecosystem health and resiliency. A dominant approach uses global climate models to predict changes in climate in the coming decades and then to downscale this information to assess impacts to plant communities, animal habitats, agricultural and urban ecosystems, and other parts of the Earth’s life system. To achieve robust assessments of the threats to these systems in this top-down, outcome vulnerability approach, however, requires skillful prediction, and representation of changes in regional and local climate processes, which has not yet been satisfactorily achieved. Moreover, threats to biodiversity and ecosystem function, such as from invasive species, are in general, not adequately included in the assessments. We discuss a complementary assessment framework that builds on a bottom-up vulnerability concept that requires the determination of the major human and natural forcings on the environment including extreme events, and the interactions between these forcings. After these forcings and interactions are identified, then the relative risks of each issue can be compared with other risks or forcings in order to adopt optimal mitigation/adaptation strategies. This framework is a more inclusive way of assessing risks, including climate variability and longer-term natural and anthropogenic-driven change, than the outcome vulnerability approach which is mainly based on multi-decadal global and regional climate model predictions. We therefore conclude that the top-down approach alone is outmoded as it is inadequate for robustly assessing risks to biodiversity and ecosystem function. In contrast the bottom-up, integrative approach is feasible and much more in line with the needs of the assessment and conservation community. A key message of our paper is to emphasize the need to consider coupled feedbacks since the Earth is a dynamically interactive system. This should be done not just in the model structure, but also in its application and subsequent analyses. We recognize that the community is moving toward that goal and we urge an accelerated pace.

A spring freeze is an unexpected freeze event occurring in late spring that can result in severe domestic crop loss. These events coincide with seasonal weather conditions that promote early crop development. As a consequence, early growth is most susceptible to freeze damage. Spring temperature fluctuations pose significant threat to crop yield and growth, when compared to onsistently cold springtime temperatures. In this study, a thirty-four-year span (1982 to 2015) of historical climate, agricultural and crop insurance data for Missouri was analyzed. Risk analysis was performed for each Missouri county to determine statistical relationships between crop loss and springtime warm-cold temperature fluctuations. Statewide, several regions were identified as having an increased susceptibility to freeze events, with Lafayette County emerging as the state’s leading county in agricultural losses due to freeze events. The window for peak freeze damage for Lafayette County was identified as the last week of March through the first week of April. The years 1985, 1996 and 2007 stood apart in the dataset as they correspond to the highest crop damages on record. Each of these years also corresponds to a doubling of severity in the reported crop losses.

The study examines the crisis of wildfire destruction in the United States and the various wildfire policies in place to mitigate the risk of wildfire. It also considers the factors affecting the incidence of wildfire in Missouri and finally it analyses the reasons for wildfire policy failure in the United States and suggestion on how to approach the challenge. The study concludes by examining the implication of social and demographic characteristics of forest landowners, land use change, wildland urban interface and climate change on wildfire risk reduction in Missouri.

Surface observations provide ground evidence of climate change to support the scientific guidance paving the way to better adaptation and mitigation actions. The West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL) has designed a multi-stakeholder initiative to rescue the deteriorated near-surface weather, climate and hydrological equipment of West African countries. The main goal for this multi-stakeholder framework was to monitor the climate and collect long term and high-quality records of essential climate variables in support of research, education, capacity building, and climate services provision. Proactive and inclusive partnership initiatives were developed to jointly (re)design and (re)implement near surface observatiories with the national meteorological and hydrological services or agencies (NMHS/As) in West Africa. The co-production scheme used by this framework succeeded in evaluating the existing observations networks, to modernizing sensors and field equipment, and densifying the sites in order to improve the quality of data collection, transmission, archiving, processing and sharing policies. After more than four years of community-of-practice, the existing regional basic hydroclimatic was increased/upgraded by 45% with automatic weather observing systems while fifty automatic water level, ten water quality sensors, three mesoscale research catchments, and several pilot sites to benefit countries’ services provision, research infrastructure, education, and capacity building. Country-specific data sharing policies were harmonized and signed to support data services delivery. This practice paper exposes the concepts, outcomes, challenges, lessons learned and the ways forward in setting-up the framework and keeping it on working to leverage the co-production of data & information services for better-informed decision-making in the field of sustainable development in West Africa.

This study investigated the spatial occurrence of cardiovascular diseases associated with the air quality of selected abattoirs in Port Harcourt. Using the simple random sampling technique, the Trans-Amadi, Rumuokoro, Rukpokwu and Elelenwo abattoirs were selected and used for the study. However, both gases and particulates matter which include NO2, SO2, H2S, CH4, CO, PM2.5, and PM10 were collected at distances of 0, 20, 50, 100, 200 m with the aid of a hand held multi-gas monitor. The questionnaire was used to obtain the demographic and socio-economic characteristics of the respondents, duration of job in years, as well as individual frequency of hospital visitation based on symptoms of cardiovascular diseases. The electrocardiogram was employed to diagnose manifestations of ischemic heart disease among the workers especially in the roasting section. Analysis of data collected was done using the Step-wise multiple regression technique. Result showed that occurrence of cardiovascular diseases is a function of pollutant concentration (CO - r = 0.57) at Rumuokoro abattoir; (O3 - r = 0.40, SO2 - r = 0.23, CO - r = 0.14) at Rukpokwu abattoir, duration of exposure (DOE - r = 0.22) at Rumuokoro abattoir, (DOE ? r = 0.40) at Trans-Amadi abattoir; and (DOE - r = 0.20) at Elelenwo abattoir; age of worker (r = 0.06) at Rukpokwu abattoir, (r = 0.30) at Elenlewo abattoir and daily duration on the job (JOBD - r = 0.13) at Elelenwo abattoir. Findings indicate that there is a positive correlation between occurrence of vascular diseases and pollutant concentration, duration of exposure, age and duration on the job but varies from location to location. Periodic epidemiological and air quality assessment of workers at the abattoirs are strongly advocated.

This study examined the hydrological modeling of aquifers and their ground water potentials for the purposes of water resources planning and management. This was done using the electrical resistivity method employing the schlumberger electrode configuration at randomly selected stations to obtain the thicknesses and resistivities of each layer and depth to the presumably conglomeratic sand stone and its resistivity. Findings showed that the top soil layer resistivity values vary from 59.3 to 248.4 ohm-m and thickness of 0.6 to 3.9 m. The second layer has resistivity values ranging from 45.0 to 743.5 ohm-m and a thickness range of 1.5 to 13.8 m. The wet sand is characterized by resistivity values ranging from 144.8 to 1930.2 ohm-m and a thickness range of 3.8 to 65.8 m. The conglomeratic sand/sand stone has resistivity values ranging from 55.8 to 7719.8 ohm-m. The depth to this bottom layer varies from 6.6 to 89.5 m. Findings indicate that the entire profile is a sedimentary formation represented by lithological units of sand and clayey sand which make for a good groundwater potentials. However, the groundwater potential zones of the study area in terms of transmisivity revealed four distinct classes representing “very good” (Mgbuosimini, Rumuigbo, Okporo, Rumuomasi and Rumuodara), “good” (Alakahia, Rumuodomaya, Oginigba and Rumuola), “moderate” (Aluu, Rumuekeni, Rumuokoro, Rumuobiakani and Rumueme), and “low” (Ogbogoro, Ozuoba, Akpajio, Elelenwo, Eliozu, Rumuepirikon, Rumuokwuta, Rumuebekwe and Rumurolu) groundwater potential in the area. Well logging should therefore be incorporated in borehole development process for safe and sustainable yield of groundwater in Obio/Akpor.

Atmospheric Black Carbon effects the hygroscopicity of cloud condensation nuclei, which in turn, effects atmospheric heating, stability, large scale circulation and overall cloud albedo. The study investigated the concentration level of soot and the surface boundary meteorology in Port Harcourt city. Sampling was done from five major different land use typologies with the aid of aeroset SPM 531, portable multi-gas monitor (Aeroqual 300 series) and Extech model 45160. Findings showed that the level of concentration of black carbon at different land use areas of Port Harcourt City was relatively very high with minimum mean value of 2.33 ± 1.66 μg/m3 and maximum mean value of 4.66 ± 5.43 (μg/m3) in the morning hours. For the evening period, the minimum mean of 1.25 ± 0.62 (μg/M3) and maximum mean of 4.75 ± 3.13 (μg/M3) For the morning study period, there was no significant difference in the level of concentration of soot at the respective land use areas, since p-values were (0.33 and 0.06); and there was significant difference in the air pollutant parameters (NO2 and CO) across the different land use areas, since p-values were (0.00 and 0.00). The meteorological predictors revealed that humidity (Beta=-0.002, p 5%) and wind speed (Beta=0.006, p 5%), temperature (Beta=-0.042, p>5%) and wind speed (Beta=0.006, p>5%). Enactment and implementation of laws against air pollution is strongly advocated.

Wildfire is a major environmental hazard causing property damage and destruction including biodiversity loss in the United States. In order to reduce property loss and destruction arising from wildfire, this study assessed and identified social vulnerability to wildfire in Missouri using the American Community Survey data on social and demographic variables for the state of Missouri and social vulnerability index (S0VI). The study divided Missouri into five geopolitical zones from which ten counties were randomly selected for this study. The selected counties formed the basis on which fourteen social and demographic indicators were identified and assessed using Bogardi, Birkmann and Cadona conceptual framework. The result of the analysis shows that S0VI estimated for the five geopolitical zones of Missouri is moderate with a rating scale of 1.42 – 1.71. Education, income and marital status have a rating scale of 2.0 - 3.0 attributed for the high value of Social Vulnerability to wildfire. Race / ethnicity, language spoken, employment and percentage of house units that are mobile homes had a low S0VI value of 1.0 thereby contributing positively to resilience to wildfire risk. The study observes that government involvement in wildfire risk reduction is quite impressive and should still be intensified. The policy implication of this study is that education and income are key variables that contribute to high wildfire risk in Missouri. The need for government to formulate a policy on environmental education of the populace especially for people of low income and education become imperative. This will go a long way in reducing damage and property loss arising from wildfire.

Air pollution has been identified to be one major problem associated with urbanisation, particularly in developing countries. In this regard, this paper utilizes data from a year-long experiment of simultaneous measurements to examine and compare the variations of carbon monoxide concentrations, a major air pollutant at urban and rural site in Akure, a medium-sized tropical city in south western Nigeria. The comparison was done to assess the urban influence on the air pollutant. CO concentrations at the urban centre have been identified to exhibit distinct diurnal and day-of-week variations with respect to traffic rush hours. It is also observed that the concentrations at the urban centre were 2 - 3 times higher than that of the rural site which exhibited a consistent cyclic diurnal pattern throughout the week. Results further identified the major cause of CO concentration in the urban centre to be vehicular as consistent increase of the air pollutant from 08:00 to 16:00 during the weekdays is found to be associated with “school runs and rush hours” and also rises through the midnight hours on days linked with social events, particularly Saturdays. In relation to human health and World Health Organisation (WHO) guidelines, results showed that CO concentrations at the urban centre exceeded the WHO 8-hour average recommendation during daytime throughout the weekdays.

Worldwide, the mangrove ecosystem is in serious decline. The continuous conversion of mangrove vegetation to alternative usage is attributable to the lack of appreciation for the many ecological services, as well as products from the vegetation. As a result, seminal studies have been conducted severally to estimate the economic value of products and services derived from mangroves. However, mangroves also exhibit social value which has been called cultural services of ecosystems, cultural capital of ecosystems and sociocultural perspective of critical natural capital. The social value of mangroves is qualitative and thus antithetical, as well as distinguishable from quantitative economic value in which money is the natural common measurement unit. It is for this very reason that the social value of mangroves is often not captured for policy- and decision-making. This study, therefore, focuses on the social valuation of mangroves in the Niger Delta region of Nigeria using the following social value variabl...

Africa's vast landmass harbors a variety of physical processes that affect the environment and the water cycle. This focus issue on 'African Environmental Processes and Water-Cycle Dynamics' contains eight articles that address these phenomena from different but complementary perspectives. Fires used for agricultural and related purposes play a major role in land-cover change, surface albedo modifications, and smoke emission; all of which affect the environment and the water cycle in different ways. However, emissions of aerosols and trace gases are not restricted to fires, but also emanate from other natural and human activities. The African water cycle undergoes significant perturbations that are attributable to several factors, including the aforesaid environmental processes. These changes in the water cycle have produced severe drought and flooding events in recent decades that affect societal wellbeing across sub-Saharan Africa. The combined effects of the environmental processes and water-cycle dynamics affect and are affected by climate variability and can be propagated beyond the continent. Future studies should utilize the wealth of observations and modeling tools that are constantly improving to clearly elucidate the interrelationships between all of these phenomena for the benefit of society.

Lake Fitri, located northeast of the Republic of Chad’s Capital, N’Djamena, and southeast of Lake Chad, is especially important because it serves as an alternative source to Lake Chad in supporting the livelihood of pastoralists and subsidence farmers displaced from the Lake Chad region. It therefore serves to relieve population pressures on Lake Chad, which has undergone drastic reduction in total water volume in the last few decades. The area has also been the epicenter of recent violent campaigns and devastating insurgency mounted by the so-called Boko Haram. This study investigated the land use land cover around Lake Fitri from 1986 to 2003, and from 2003 to 2013 using Landsat 5 (TM), Landsat 7 (ETM+), and Landsat 8 (OLI_TIRS). The satellite imageries were retrieved from the Global Visualization (GloVis) web-based platform and analyzed using ERDAS Imagine 2014. Supervised classification of areas around the lake was performed into five land use land cover classes. The results revealed significant changes in three land use types, namely Farmland and Grassland combined, Forest, Savanna, and Steppe combined, and Wetland. Farmland and Grassland combined increased from a mere 0.38% of the total study area in 1986 to 41.05% in 2013. At the same time, Forest, Savanna, and Steppe combined decreased from about 23% in 1986 to about 7.40% in 2013. This increase in farmlands and grasslands coverage and the concomitant decrease in trees and shrubs can be explained by the persistent pressures on land from increasing population and livestock in the area. The findings also show a major decline in Wetland, which decreased from about 14% of the total study area to 3% in the same time period. This loss in wetland coverage is regrettable because of the important environmental and ecological functions of wetlands.

Several recommendations have been proposed for detecting land use and land cover change (LULCC) on the environment from, observed climatic records and to modeling to improve its understanding and its impacts on climate. Researchers need to detect LULCCs accurately at appropriate scales within a specified time period to better understand their impacts on climate and provide improved estimates of future climate. The US Climate Reference Network (USCRN) can be helpful in monitoring impacts of LULCC on near-surface atmospheric conditions, including temperature. The USCRN measures temperature, precipitation, solar radiation, and ground or skin temperature. It is recommended that the National Climatic Data Center (NCDC) and other climate monitoring agencies develop plans and seek funds to address any monitoring biases that are identified and for which detailed analyses have not been completed.

In Part I of this observational study inquiring into the relative influences of “top down” synoptic atmospheric conditions and “bottom up” land surface mesoscale conditions in deep convection for the humid lowlands of the Midwest U.S. Central Corn Belt (CCB), the composite atmospheric environments for afternoon and evening periods of convection (CV) versus no convection (NC) were determined for two recent summers (1999 and 2000) having contrasting precipitation patterns and amounts. A close spatial correspondence was noted between composite synoptic features representing baroclinity and upward vertical motion with the observed precipitation on CV days when the “background” (i.e., free atmosphere) wind speed exceeded approximately 10 m s−1 at 500 hPa (i.e., “stronger flow”). However, on CV days when wind speeds were For the 1999 and 2000 summers (item 1 above), thermodynamic composites determined for V(500) categories having minimal differences in synoptic meteorological fields on CV minus NC (CV − NC) days (i.e., weaker flow), show statistically significant increases in atmospheric moisture (e.g., greater precipitable water; lower LCL and LFC) and static instability [e.g., positive convective available potential energy (CAPE)] compared to NC days. Moreover, CV days for both weaker and stronger background flow have associated subregional-scale thermodynamic patterns indicating free convection at the earth’s surface, supported by a synoptic pattern of at least weakly upward motion of air in the midtroposphere in contrast to NC days. The possibility that aerodynamic contrasts along QPVBs readily permit air to be lofted above the LFC when the lower atmosphere is moist, thereby assisting or enhancing deep convection on CV days, is supported by the multiyear analysis (item 2 above). In early summer when LULC boundaries are most evident, precipitation on weaker flow days is significantly greater within 20 km of boundaries than farther away, but there is no statistical difference on stronger flow days. Statistical relationships between boundary mean attributes and mean precipitation change sign between early summer (positive) and late summer (negative), in accord with shifts in the satellite-retrieved maximum radiances from forest to crop areas. These phenological changes appear related, primarily, to contrasting soil moisture and implied evapotranspiration differences. Incorporating LULC boundary locations and phenological status into reliable forecast fields of lower-to-midtropospheric humidity and wind speed should lead to improved short-term predictions of convective precipitation in the Corn Belt and also, potentially, better climate seasonal forecasts.

In the Midwest U.S. Corn Belt, the 1999 and 2000 summer seasons (15 June–15 September) expressed contrasting spatial patterns and magnitudes of precipitation (1999: dry; 2000: normal to moist). Distinct from the numerical modeling approach often used in studies of land surface–climate interactions, a “synoptic climatological” (i.e., stratified composite) approach is applied to observation data (e.g., precipitation, radar, and atmospheric reanalyses) to determine the relative influences of “top-down” synoptic atmospheric circulation (Part I, this paper) and “bottom-up” land surface mesoscale conditions (Part II) on the predominantly convective precipitation variations. Because mesoscale modeling suggests that the free-atmosphere wind speed (“background wind”) regulates the land surface–atmosphere mesoscale interaction, each day’s spatial range of wind speed at 500 hPa [V(500)] over the Central Corn Belt (CCB) is classified into one of five categories ranging from “weak flow” to “jet maximum.” Deep convective activity (i.e., presence/absence and morphological signature type) is determined for each afternoon and early evening period from the Next Generation Weather Radar (NEXRAD) imagery. Frequencies of the resulting background wind–convection joint occurrence types for the 1999 and 2000 summer seasons are examined in the context of the statistics determined for summers in the longer period of 1996–2001, and also compose categories for which NCEP–NCAR reanalysis (NNR) fields are averaged to yield synoptic composite environments for the two study seasons. The latter composites are compared visually with high-resolution (spatial) composites of precipitation to help identify the influence of top-down climate controls. The analysis confirms that reduced (increased) organization of radar-indicated deep convection tends to occur with weaker (stronger) background flow. The summers of 1999 and 2000 differ from one another in terms of background flow and convective activity, but more so with respect to the six-summer averages, indicating that a fuller explanation of the precipitation differences in the two summers must be sought in the analysis of additional synoptic meteorological variables. The composite synoptic conditions on convection (CV) days (no convection (NC) days) in 1999 and 2000 are generalized as follows: low pressure incoming from the west (high pressure or ridging), southerly (northerly) lower-tropospheric winds, positive (negative) anomalies of moisture in the lower troposphere, rising (sinking) air in the midtroposphere, and a location south of the upper-tropospheric jet maximum (absence of an upper-tropospheric jet or one located just south of the area). Features resembling the “northerly low-level jets” identified in previous studies for the Great Plains are present on some NC-day composites. On CV days the spatial synchronization of synoptic features implying baroclinity increases with increasing background wind speed. The CV and NC composites differ least on days of weaker flow, and there are small areas within the CCB having no obvious association between precipitation elevated amounts and synoptic circulation features favoring the upward motion of air. These spatial incongruities imply a contributory influence of “stationary” (i.e., climatic) land surface mesoscale processes in convective activity, which are examined in Part II.

Deaths resulting from CO poisoning has been a recurrent incidence in the city of Port Harcourt especially from risky behaviors, such as improper placement of power generating sets and indoor use of charcoal grills. Domestic CO poisoning is rarely reported and remains an under recognized problem. This study therefore examined the concentration of Carbon Monoxide (CO) as influenced by both landuse and meteorological parameters of wind speed, relative humidity, ambient temperature and rainfall in the industrial city of Port Harcourt. Air quality and meteorological data were measured at twelve stations: two each from the industrial, high and low density residential, commercial, transportation and surrounding rural areas. Data were collected for seven weeks during wet, transition and dry seasons. Analysis of data was done using ANOVA and stepwise multiple regression techniques. Result showed that during the wet season, wind speed was significant at 99% in impacting the concentration of CO at the low density residential areas of GRA and Abuloma housing estates. The coefficient of determination value (22.9%) showed that jointly, the meteorological variable accounted for 23.9% of the variation in the concentration of CO during the wet season at the low density residential areas. At the rural areas, the correlation matrix shows that both rainfall (-0.117) and wind speed (-0.318) correlated inversely with CO during the wet season. But air temperature (0.005) and relative humidity (0.268) correlated directly with CO. Generally, the mean weekly concentration of CO revealed that the industrial areas accounted for 28.8%, 26.7% and 22.1% of the total atmospheric loading of CO during the transition, dry and wet season respectively. Further studies are needed to link exposure to CO with mortality and morbidity.

This study was carried out with the primary aim of understanding how the mangrove ecosystem in the Niger Delta has been altered recently. Specifically, we determined the spatial extent of the mangrove forest in the Niger Delta using remotely sensed satellite data and estimated changes in the spatial extent of the forest from the mid-1980s through 2003. Overall, about 21,340 hectares of Mangrove forest was lost over the study period. Fieldwork confirmed that these losses were primarily due to urbanization, dredging activities, activities of the oil and gas industries, and the spread of Nypa Palm (Nypa frutican) plant species.

Fifty-three years of the NCEP–NCAR Reanalysis I are dynamically downscaled using the Regional Atmospheric Modeling System (RAMS) to generate a regional climate model (RCM) climatology of the contiguous United States and Mexico. Data from the RAMS simulations are compared to the recently released North American Regional Reanalysis (NARR), as well as observed precipitation and temperature data. The RAMS simulations show the value added by using a RCM in a process study framework to represent North American summer climate beyond the driving global atmospheric reanalysis. Because of its enhanced representation of the land surface topography, the diurnal cycle of convective rainfall is present. This diurnal cycle largely governs the transitions associated with the evolution of the North American monsoon with regards to rainfall, the surface energy budget, and surface temperature. The lower frequency modes of convective rainfall, though weaker, account for rainfall variability at a remote distance from elevated terrain. As in previous studies with other RCMs, RAMS precipitation is overestimated compared to observations. The Great Plains low-level jet (LLJ) is also well represented in both RAMS and NARR, but the Baja LLJ and associated gulf surges are not.

Summer simulations over the contiguous United States and Mexico with the Regional Atmospheric Modeling System (RAMS) dynamically downscaling the NCEP–NCAR Reanalysis I for the period 1950–2002 (described in Part I of the study) are evaluated with respect to the three dominant modes of global SST. Two of these modes are associated with the statistically significant, naturally occurring interannual and interdecadal variability in the Pacific. The remaining mode corresponds to the recent warming of tropical sea surface temperatures. Time-evolving teleconnections associated with Pacific SSTs delay or accelerate the evolution of the North American monsoon. At the period of maximum teleconnectivity in late June and early July, there is an opposite relationship between precipitation in the core monsoon region and the central United States. Use of a regional climate model (RCM) is essential to capture this variability because of its representation of the diurnal cycle of convective rainfall. The RCM also captures the observed long-term changes in Mexican summer rainfall and suggests that these changes are due in part to the recent increase in eastern Pacific SST off the Mexican coast. To establish the physical linkage to remote SST forcing, additional RAMS seasonal weather prediction mode simulations were performed and these results are briefly discussed. In order for RCMs to be successful in a seasonal weather prediction mode for the summer season, it is required that the GCM provide a reasonable representation of the teleconnections and have a climatology that is comparable to a global atmospheric reanalysis.

This paper discusses the diverse climate forcings that impact agricultural systems, and contrasts the current paradigm of using global models downscaled to agricultural areas (a top-down approach) with a new paradigm that first assesses the vulnerability of agricultural activities to the spectrum of environmental risk including climate (a bottom-up approach). To illustrate the wide spectrum of climate forcings, regional climate forcings are presented including land-use/land-cover change and the influence of aerosols on radiative and biogeochemical fluxes and cloud/precipitation processes, as well as how these effects can be teleconnected globally. Examples are presented of the vulnerability perspective, along with a small survey of the perceived drought impacts in a local area, in which a wide range of impacts for the same precipitation deficits are found. This example illustrates why agricultural assessments of risk to climate change and variability and of other environmental risks should start with a bottom-up perspective.

The impact of agricultural land use change on atmospheric boundary layer processes, the associated feedbacks and their regional scale impacts, are examined with particular emphasis on the central United States. Specifically, the role of contrasting forested and agriculturallandcoversintheinitiationandsubsequentevolutionofsummertimecloudpatternsintheU.S.Midwest;andtheimpact of agricultural practices, including irrigation, on the surface climate of the U.S. High Plains are discussed in detail. Satellite-based observational results of previous work summarized in this paper indicate that the timing and intensity of cloud development appears to be influenced by both synoptic flow regimes and agricultural land use type. For example, under conditions characterized by high pressure with surface winds generally less than 5 m s � 1 , peak cloud development occurred almost two hours earlier over cropland than over the forest or boundary locations in Michigan. Cloud masses were also considerably taller over cropland in the midafternoon than over forest and land cover transition zones. The modeling results discussed here for a model domain centered over Nebraska indicate significant differences in the surface energy fluxes between the irrigated (control) and non-irrigated (dry) simulations. Surface latent heat flux was higher by 36% and dewpoint temperature higher by 2.3 8C in the control simulation. Also, surfacesensible heatfluxof thecontrolsimulationwas15%less and thenear-ground (2 m)temperaturewas1.2 8Cless compared to dry run, indicating irrigation-induced surface cooling effect. Recent investigations on crop‐climate interactions in which crop and ecological models were coupled to regional climate models show that incorporating important perturbations such as prolonged droughtsand the resulting changesin soil and plant nutrient conditionsremains one ofthe biggest challenges in developingeffective and realistic ecological-climate integrated modeling systems. # 2006 Elsevier B.V. All rights reserved.

Tropical rainfall measuring mission (TRMM) TRMM microwave imager (TMI) retrieved total precipitable water (TPW) has been shown in previous studies to be useful for characterizing energy transport and rainfall variability over water bodies. In this study, 3-day composite TPW values during the monsoon months of June–September in 1999 and 2003 were evaluated against radiosonde derived TPW over the coastal regions of Indian Ocean. The radiosonde measurements were from coastal locations, island stations and ship-based observations made during the 1999 Bay of Bengal Monsoon Experiment (BOBMEX). Our study is one of the first attempts to compare TMI-derived TPW with the BOBMEX data. Root mean square (RMS) error of 8.1 mm and a bias of −0.76 mm were obtained for TMI 3-day composite TPW data with respect to the radiosonde data over the Indian coastal regions. TMI overestimated (underestimated) radiosonde measurements under dry (wet) atmospheric conditions. Daily TMI-derived TPW was also validated with radiosonde measurements from the BOBMEX data for the period 21 July–28 August 1999. Diurnal signals of TPW over Bay of Bengal were found to be comparable to the in situ measurements during the same period. Copyright © 2006 Royal Meteorological Society

A storm-resolving version of the Regional Atmospheric Modeling System is executed over St. Louis, Missouri, on 8 June 1999, along with sophisticated boundary conditions, to simulate the urban atmosphere and its role in deep, moist convection. In particular, surface-driven low-level convergence mechanisms are investigated. Sensitivity experiments show that the urban heat island (UHI) plays the largest role in initiating deep, moist convection downwind of the city. Surface convergence is enhanced on the leeward side of the city. Increased momentum drag over the city induces convergence on the windward side of the city, but this convergence is not strong enough to initiate storms. The nonlinear interaction of urban momentum drag and the UHI causes downwind convection to erupt later, because momentum drag over the city regulates the strength of the UHI. In all simulations including a UHI, precipitation totals are enhanced downwind of St. Louis. Topography around St. Louis also affects storm development. There is a large sensitivity of simulated urban-enhanced convection to the details of the urban surface model.

The impact of irrigation on the surface energy budget in the U.S. high plains is investigated. Four 15-day simulations were conducted: one using a 1997 satellite-derived estimate of farmland acreage under irrigation in Nebraska (control run), two using the Olson Global Ecosystem (OGE) vegetation dataset (OGE wet run and OGE dry run), and the fourth with the Kuchler vegetation dataset (natural vegetation run) as lower boundary conditions in the Colorado State University Regional Atmospheric Modeling System (RAMS). In the control and OGE wet simulations, the topsoil in the irrigated locations, up to a depth of 0.2 m, was saturated at 0000 UTC each day for the duration of the experiment (1‐15 July 1997). In the other two runs, the soil was allowed to dry out, except when replenished naturally by rainfall. Identical observed atmospheric conditions were used along the lateral boundary in all four cases. The area-averaged model-derived quantities for the grid centered over Nebraska indicate significant differences in the surface energy fluxes between the control (irrigated) and the ‘‘dry’’ simulations. For example, a 36% increase in the surface latent heat flux and a 2.6 8C elevation in dewpoint temperature between the control run and the OGE dry run is shown. Surface sensible heat flux of the control run was 15% less and the near-ground temperature was 1.28C less compared to the OGE dry run. The differences between the control run and the natural vegetation run were similar but amplified compared to the control run‐OGE dry run comparisons. Results of statistical analyses of long-term (1921‐2000) surface temperature data from two sites representing locations of extensive irrigated and nonirrigated land uses appear to support model results presented herein of an irrigationrelated cooling in surface temperature. Growing season monthly mean and monthly mean maximum temperature data for the irrigated site indicate a steady decreasing trend in contrast to an increasing trend at the nonirrigated site.

Snow cover can significantly suppress daytime temperatures by increasing the surface albedo and limiting the surface temperature to 0°C. The strength of this effect is dependent upon how well the snow can cover, or mask, the underlying surface. In regions where tall vegetation protrudes through a shallow layer of snow, the temperature-reducing effects of the snow will be suppressed since the protruding vegetation will absorb solar radiation and emit an upward turbulent heat flux. This means that an atmospheric model must have a reasonable representation of the land cover, as well as be able to correctly calculate snow depth, if an accurate simulation of surface heat fluxes, air temperatures, and boundary layer structure is to be made. If too much vegetation protrudes through the snow, then the surface sensible heat flux will be too large and the air temperatures will be too high. In this study four simulations are run with the Regional Atmospheric Modeling System (RAMS 4.30) for a snow event that...

Satellite-derived vegetation indices extracted over locations representative of midwestern U.S. cropland and forest for the period 1990–94 are analyzed to determine the sensitivity of the indices to neutron probe soil moisture measurements of the Illinois Climate Network (ICN). The deseasoned (i.e., departures from multiyear mean annual cycle) soil moisture measurements are shown to be weakly correlated with the deseasoned full resolution (1 km × 1 km) normalized difference vegetation index (NDVI) and fractional vegetation cover (FVC) data over both land cover types. The association, measured by the Pearson-moment-correlation coefficient, is stronger over forest than over cropland during the growing season (April–September). The correlations improve successively when the NDVI and FVC pixel data are aggregated to 3 km × 3 km, 5 km × 5 km, and 7 km × 7 km areas. The improved correlations are partly explained by the reduction in satellite navigation errors as spatial aggregation occurs, as well as t...

Human-induced land cover modifications impact the planetary boundary layer's (PBL) thermal and moisture regimes on mesoscales. We investigate the association of croplands, forest, and the crop-forest “boundary” (CFB) with convective-cloud development (timing, amount) for three target areas (TAs) in the U.S. Midwest “Corn Belt”, during the summer seasons (JJA) 1991–98. For each land cover, hourly satellite-retrieved albedo and cloud-top temperature values are composited for three classes of mid-tropospheric synoptic circulation. On days with the strongest anticyclonicity, there are no consistent differences in convection related to land cover type: cloud development is regionalized and tied primarily to synoptic conditions. However, on days having weaker anticyclonicity the CFB is the dominant site of free convection, suggesting that Non-Classical Mesoscale Circulations (NCMCs) between cropped and adjacent forest areas may operate when reduced subsidence in the mid-troposphere does not effectively cap the PBL. Index terms: Land/atmosphere interactions (3322), Mesoscale meteorology (3329), Climate dynamics (1620), Anthropogenic effects (1803).

The Northern Sub-Saharan African (NSSA) region, which accounts for 20%-25%of the global carbon emissions from biomass burning, also suffers from frequent drought episodes and other disruptions to the hydrological cycle whose adverse societal impacts have been widely reported during the last several decades. This paper presents a conceptual framework of the NSSA regional climate system components that may be linked to biomass burning, as well as detailed analyses of a variety of satellite data for 2001-2014 in conjunction with relevant model-assimilated variables. Satellite fire detections in NSSA show that the vast majority (greater than 75%) occurs in the savanna and woody savanna land-cover types. Starting in the 2006-2007 burning season through the end of the analyzed data in 2014, peak burning activity showed a net decrease of 2-7% /yr in different parts of NSSA, especially in the savanna regions. However, fire distribution shows appreciable coincidence with land-cover change. Although there is variable mutual exchange of different land cover types, during 2003-2013, cropland increased at an estimated rate of 0.28% /yr of the total NSSA land area, with most of it (0.18% /yr) coming from savanna.During the last decade, conversion to croplands increased in some areas classified as forests and wetlands, posing a threat to these vital and vulnerable ecosystems. Seasonal peak burning is anti-correlated with annual water-cycle indicators such as precipitation, soil moisture, vegetation greenness, and evapotranspiration, except in humid West Africa (5 deg-10 deg latitude),where this anti-correlation occurs exclusively in the dry season and burning virtually stops when monthly mean precipitation reaches 4 mm/d. These results provide observational evidence of changes in land-cover and hydrological variables that are consistent with feedbacks from biomass burning in NSSA, and encourage more synergistic modeling and observational studies that can elaborate this feedback mechanism.

We discuss the adoption of a bottom-up, resource-based vulnerability approach in evaluating the effect of climate and other environmental and societal threats to societally critical resources. This vulnerability concept requires the determination of the major threats to local and regional water, food, energy, human health, and ecosystem function resources from extreme events including those from climate but also from other social and environmental issues. After these threats are identified for each resource, then the relative risks can be compared with other risks in order to adopt optimal preferred mitigation/adaptation strategies. This is a more inclusive way of assessing risks, including from climate variability and climate change, than using the outcome vulnerability approach adopted by the Intergovernmental Panel on Climate Change (IPCC). A contextual vulnerability assessment using the bottom-up, resource-based framework is a more inclusive approach for policy makers to adopt effective mitigation and adaptation methodologies to deal with the complexity of the spectrum of social and environmental extreme events that will occurinthecomingdecadesastherangeofthreatsareassessed,beyondjustthefocus on CO2 and a few other greenhouse gases as emphasized in the IPCC assessments.

In Nigeria, there is dearth of studies on recent changes on accelerated marine processes along the national coastlines despite their importance as ports for navigation and marine commerce as well as a bridge for aquatic and terrestrial life.This study, which deals with a time series analysis of recent changes in the Niger Delta Coastline using Satellite Imagery is an attempt at filling this gap. Landsat TM images of 1986 and Landsat ETM+ of 2003 both covering the Niger Delta area of Nigeria were used for this study and the images were processed using Erdas Imagine Version 8.7 and Arc Info 9.1 for the GIS operations. The results of the analyses show among other things that coastline erosion was dominant over accretion of sediment deposition. Also that the total area of observed changes along the coastlines was 46.535sq.km. Of this, 27.65sq.km (59.43%) constitutes eroded area, and 40.57% representing 18.88sq.km of the area showed coastal sediment accretion.

Tropospheric ozone concentrations for Kansas City are well known on a regional scale. The Kansas City, Missouri, ground-level ozone (GLO) project measured outdoor ozone concentrations using passive sensing devices (PSDs) on a neighborhood scale. Highly resolved exposure maps were made based on the detailed air quality observations collected during the seven week sampling study during the summer of 2005. Data analysis demonstated that ozone concentration levels were higher in urban core neighborhoods compared to the surrounding surbuban areas. The results have negative implications for the respiratory health of residents of urban Kansas City.

Previous measurements of urban energy balances generally have been limited to densely built, central city sites and older suburban locations with mature tree canopies that are higher than the height of the buildings. In contrast, few data are available for the extensive, open vegetated types typical of low-density residential areas that have been newly converted from rural land use. We made direct measurements of surface energy fluxes using the eddy-covariance technique at Greenwood, a recently developed exurban neighbourhood near Kansas City, Missouri, USA, during an intensive field campaign in August 2004. Energy partitioning was dominated by the latent heat flux under both cloudy and near clear-sky conditions. The mean daytime Bowen ratio (β) values were 0.46, 0.48, and 0.47 respectively for the cloudy, near clear-sky and all-sky conditions. Net radiation (R n ) increased rapidly from dawn (−34 and −58W m−2) during the night to reach a maximum (423 and 630W m−2) after midday for cloudy and near clear-sky conditions respectively. Mean daytime values were 253 and 370W m−2, respectively for the cloudy and near clear-sky conditions, while mean daily values were 114 for cloudy and 171W m−2 for near clear-sky conditions, respectively. Midday surface albedo values were 0.25 and 0.24 for the cloudy and near clear-sky conditions, respectively. The site exhibited an angular dependence on the solar elevation angle, in contrast to previous observations over urban and suburban areas, but similar to vegetated surfaces. The latent heat flux (Q E ), sensible heat flux (Q H ), and the residual heat storage ΔQ s terms accounted for between 46–58%, 21–23%, and 18–31% of R n , respectively, for all-sky conditions and time averages. The observed albedo, R n , and Q E values are higher than the values that have been reported for suburban areas with high summer evapotranspiration rates in North America. These results suggest that the rapidly growing residential areas at the exurban fringe of large metropolitan areas have a surface energy balance that is more similar to the rural areas from which they were developed than it is to the older suburbs and city centres that make up the urban fabric to which they are being joined.

In this study, the combined effect of the Atlantic Multidecadal Oscillation (AMO) and El Nino Southern Oscillation (ENSO) on the Lake Chad (LC) level variability is explored. Our results show that the lake level at the Bol monitoring station has a statistically significant correlation with precipitation (R2 = 0.6, at the 99.5% confidence level). The period between the late 1960s and early 1970s marked a turning point in the response of the regional rainfall to climatic drivers, thereby severely affecting the LC level. Our results also suggest that the negative impact of the cold phase of AMO on Sahel precipitation masks and supersedes the positive effect of La Nina in the early the 1970s. The drop in the size of LC level from 282.5 m in the early 1960s to about 278.1 m in 1983/1984 was the largest to occur within the period of study (1900–2010) and coincides with the combined cold phase of AMO and strong El Nino phase of ENSO. Further analyses show that the current warm phase of AMO and increasing...

An analysis of observed trends in African annual-average near-surface temperatures over the last five decades reveals drastic increases, particularly over parts of the subtropics and central tropical Africa. Over these regions, temperatures have been rising at more than twice the global rate of temperature increase. An ensemble of high-resolution downscalings, obtained using a single regional climate model forced with the sea-surface temperatures and sea-ice fields of an ensemble of global circulation model (GCM) simulations, is shown to realistically represent the relatively strong temperature increases observed in subtropical southern and northern Africa. The amplitudes of warming are generally underestimated, however. Further warming is projected to occur during the 21st century, with plausible increases of 4-6 C over the subtropics and 3-5 C over the tropics by the end of the century relative to present-day climate under the A2 (a low mitigation) scenario of the Special Report on Emission Scenarios. High impact climate events such as heat-wave days and high fire-danger days are consistently projected to increase drastically in their frequency of occurrence. General decreases in soil-moisture availability are projected, even for regions where increases in rainfall are plausible, due to enhanced levels of evaporation. The regional downscalings presented here, and recent GCM projections obtained for Africa, indicate that African annual-averaged temperatures may plausibly rise at about 1.5 times the global rate of temperature increase in the subtropics, and at a somewhat lower rate in the tropics. These projected increases although drastic, may be conservative given the model underestimations of observed temperature trends. The relatively strong rate of warming over Africa, in combination with the associated increases in extreme temperature events, may be key factors to consider when interpreting the suitability of global mitigation targets in terms of African climate change and climate change adaptation in Africa.

[1] This study utilizes a satellite-based methodology to assess the urban heat-island influence during warm season months for over 4400 stations included in the Global Historical Climatology Network of climate stations. The methodology includes local and regional satellite retrievals of an indicator of the presence green photosynthetically active vegetation at and around the stations. The difference in local and regional samples of the normalized difference vegetation index (NDVI) is used to estimate differences in mean air temperature. Stations classified as urban averaged 0.90°C (N. Hemisphere) and 0.92°C (S. Hemisphere) warmer than the surrounding environment on the basis of the NDVI-derived temperature estimates. Additionally, stations classified as rural averaged 0.19°C (N. Hemisphere) and 0.16°C (S. Hemisphere) warmer than the surrounding environment. The NDVI-derived temperature estimates were found to be in reasonable agreement with temperature differences observed between climate stations. The results suggest that satellite-derived data sets can be used to estimate the urban heat-island temperature influence on a global basis and that a more detailed analysis of rural stations and their surrounding environment may be necessary to assure that temperature trends derived from assumed rural environments are not influenced by changes in land use/land cover.

The United States Midwest over the last two decades has experienced marked warm season climate anomalies, including droughts and major floods. While the development of these extreme events can usually be traced to anomalies in atmospheric circulation, and may include teleconnections, studies based on model simulations have shown that land surface forcing may be partly responsible for the persistence of these climate anomalies. This study evaluates the presence and strength of long-term land surface-climate interactions in the U.S. Midwest. We do this via an analysis of the cross-seasonal (spring and summer) associations between temperature and moisture (Palmer Drought Severity Index-PDSI, Crop Moisture-Z Index, and precipitation) anomalies. Direct and lag correlations for the 1895–1995 and 1948–1995 periods show that warm and dry summers tend to follow warm spring seasons. These results imply that springtime precipitation anomalies may help to determine the temperature regime of the following summer, possibly via the moisture content of the upper soil. We also show that broad land cover types tend to modulate summer climate anomalies in the U. S. Midwest.

Land-use and land-cover changes (LULCC) significantly affect weather and climate as iswell documented in the scientific literature. These impacts include changes in air temperature, precipitation, atmospheric moisture content, energy fluxes, and mesoscale and potentially large-scale circulations. Recently, the United States National Research Council (2005) highlighted the importance of LULCC and recommended the broadening of the climate-change issue to include land-use/land-cover processes as an important climate forcing. The report noted that, “Regional variations in radiative forcing may have important regional and global climatic implications that are not resolved by the concept of global mean radiative forcing. Tropospheric aerosols and landscape changes have particularly heterogeneous forcings. To date, there have been only limited studies of regional radiative forcing and response. Indeed, it is not clear how best to diagnose a regional forcing and response in the observational record; regional forcings can lead to global climate responses, while global forcings can be associated with regional climate responses. Regional diabatic heating can also cause atmospheric teleconnections that influence regional climate thousands of kilometres away from the point of forcing. Improving societally relevant projections of regional climate impacts will require a better understanding of the magnitudes of regional forcings and the associated climate responses.” Therefore, it is critical that we further investigate and understand the impacts of LULCC on weather and climate predictability. In this context, an National Science Foundation (NSF) funded workshop was organized in Boulder, Colorado, USA in 2007 to further highlight the importance of LULCC, to present results of new research in LULCC, and to discuss the challenges of the monitoring and modelling of LULCC at various temporal and spatial scales. The articles included in this

This paper documents the diverse role of land-use/land-cover change on precipitation. Since land conversion continues at a rapid pace, this type of human disturbance of the climate system will continue and become even more significant in the coming decades.DOI: 10.1111/j.1600-0889.2007.00251.x