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This study compared the differences in the wave climate in the South China Sea and North Indian Ocean under these two datasets: ERA-40 wave reanalysis and Mei's hindcast wave data. In the numerical calculation of regional ocean waves, the wave climate characteristics exhibited significant bias if the influence of external swells (swells from afar) was not fully considered, which may provide an incorrect basis for global climate change analysis. 1) The trends of the significant wave height (SWH) obtained from the two datasets showed significant differences, such as those of the Bay of Bengal and the Java Sea in June–July–August. For the past 45 years, SWH from ERA-40 (SWH-ERA) exhibited a significant annual increase in low-latitude waters of the North Indian Ocean (0.2–0.6 cm yr−1) and South China Sea (0.2–0.8 cm yr−1). 2) In the Bay of Bengal, the SWH-ERA in each month was generally 0.5 m higher than the SWH from Mei's hindcast wave data (SWH-Mei) and can reach 1.0 m higher in some months. 3) In the Bay of Bengal, SWH-ERA and SWH-Mei increased significantly at annual rates of 0.13 and 0.27 cm yr−1, respectively. This increasing trend was mainly reflected after 1978. SWH-ERA showed a trough in 1975 (1.33 m) and a crest in 1992 (1.83 m), which were not reflected in SWH-Mei. [ABSTRACT FROM AUTHOR]

Climate change harms the households of coastal areas in Bangladesh because of the geographical position and changes in the climatic elements that are primarily at play. This study looks at the pattern of two prominent climatic elements: temperature and precipitation over thirty years, from 1992 to 2021, focusing on how those factors have changed. The findings revealed an upward increase in all elements, i.e., the maximum temperature, the lowest temperature, and the amount of precipitation. Using the Livelihood Vulnerability Index, this research looked at how vulnerable households are to the effects of climate change in the southwestern coastal area, namely in Amadi Union and Koyra Upazila in the Khulna district of Bangladesh. The original data came from a survey of 276 households and secondary data on rainfall and temperature for the period beginning in 1992 and continuing through 2021. The research conducted a comparative analysis to determine the household's vulnerability to climate change. The empirical research found that families in the Amadi union were moderately exposed to the effects of climate change and the weather variability regarding their strategies for making a living, their social networks, the food they have, and their level of health. By considering the socio-demographic elements, social networks, livelihoods, natural disasters, and climate variability, households of the Amadi union were equally vulnerable regarding their adaptation potential and exposure. These findings have implications for the governments, donor agencies, and other relevant agencies in Amadi Union, Koyra Upazila, and Khulna, initiating and implementing initiatives to adapt to climate change and increase household resilience. [ABSTRACT FROM AUTHOR]

The recognition on the trend of wind energy stability is still extremely rare, although it is closely related to acquisition efficiency, grid connection, equipment lifetime, and costs of wind energy utilization. Using the 40-year (1979–2018) ERA-Interim data from the European Center for Medium-Range Weather Forecasts, this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore wind energy as well as the abrupt phenomenon of wind energy stability in key regions over the past 40 years with the climatic analysis method and Mann-Kendall (M-K) test. The results show the following 5 points. (1) According to the coefficient of variation (Cv) of the wind power density, there are six permanent stable zones of global offshore wind energy: the southeast and northeast trade wind zones in the Indian, Pacific and Atlantic oceans, the Southern Hemisphere westerly, and a semi-permanent stable zone (North Indian Ocean). (2) There are six low-value zones for both seasonal variability index (Sv) and monthly variability index (Mv) globally, with a similar spatial distribution as that of the six permanent stable zones. Mv and Sv in the Arabian Sea are the highest in the world. (3) After Cv, Mv and Sv are comprehensively considered, the six permanent stable zones have an obvious advantage in the stability of wind energy over other sea areas, with Cv below 0.8, Mv within 1.0, and Sv within 0.7 all the year round. (4) The global stability of offshore wind energy shows a positive climatic trend for the past four decades. Cv, Mv and Sv have not changed significantly or decreased in most of the global ocean during 1979 to 2018. That is, wind energy is flat or more stable, while the monthly and seasonal variabilities tend to shrink/smooth, which is beneficial for wind energy utilization. (5) Cv in the low-latitude Pacific and Mv and Sv in both the North Indian Ocean and the low-latitude Pacific have an obvious abrupt phenomenon at the end of the 20th century. [ABSTRACT FROM AUTHOR]

The mountain cryosphere is crucial for socio-economic processes, especially during the dry seasons. However, anthropogenic climate change has had a detrimental impact on the cryosphere due to its sensitivity. Over the past two decades, there has been a decline in precipitation and a temperature rise, leading to a substantial reduction in the timing and extent of snow cover. This increase in temperature also elevates the snow line elevation (SLE), further diminishing the volume of available freshwater in the snow-driven basins of the Andes. In this study, we use 22 years (2000–2021) of 8-day snow product (MOD10A2) from the Moderate Resolution Imaging Spectroradiometer (MODIS) to analyze the annual and seasonal variability of snow cover area, SLE, and snow persistence (SP, an indicator of the duration of snow) in the Yeso River basin in Central Chile and the correlation of SP and SLE with hydrometeorological variables and climatic indices. We introduce a new approach called the Maximum Dissimilarity Method to obtain the SLE even on cloudy days. The results are as follows: (1) Snow cover area reductions of 34.0 km2 at low elevations in spring and 86.5 km2 at mid elevations in summer were found when comparing the period 2016–2021 to 2000–2004; (2) SP trends at the annual scale revealed a significant decrease in 89% of its area and an average of 3.6 fewer days of snow cover per year; (3) an upward and significant trend of 21 m‧year−1 in the annual SLE was found; and (4) annual SP and SLE were highly correlated with annual hydrometeorological variables, and spring and summer snow variables were significantly correlated with dry streamflow. This methodology can potentially serve as a valuable tool for detecting trends in snow-covered surfaces, and thereby associate these changes with climate change or other anthropogenic effects in future research. [ABSTRACT FROM AUTHOR]

Climate change poses a major sustainability challenge, with potential far-reaching economic and social impacts, including fluctuations in agricultural yields and subsequent volatility in the availability and prices of essential food resources. In this study, we analyze the changes in climatic variables and agricultural yields for main crops cultivated in the Abruzzo Region (Central Italy), as well as their reciprocal correlation pattern in the time range, 1952–2014. Central Italy exhibits a well-developed agricultural sector and is characterized by a Mediterranean climate; given its proximity to the semi-arid and arid North African climate zone, such a region may be particularly vulnerable to climate change impacts. The analysis reveals an increase in drought intensity and persistence, starting from the 1980s, with a shift towards more temperate conditions in winter months and a transition to a warmer and more arid climate during the summer season. Moreover, the study identifies an overall increase in the correlation magnitude between crop yield fluctuations and climatic variables in the period 1983–2014 compared to that during the previous thirty-year time range. This finding can be interpreted as a change in the resilience (or increased vulnerability) of the agricultural production system to climate change. This work can be thus considered as an interesting case study in the Mediterranean region, offering valuable insights for constructing probabilistic models of fluctuations in agricultural production possibly induced by climate change. [ABSTRACT FROM AUTHOR]

Cabbeling due to mixing of the surface waters from the Bering Strait and the Chukchi Sea is evaluated quantitatively and variations of its impact on seasonal and climatic scale are analyzed. The cabbeling effect increases additionally the mixed water density in 0.059 kg/m3 in summer and in 0.001 kg/m3 in winter. Seasonal variation of the cabelling repeats the seasonal variation of temperature difference between the interacted water masses (ΔT ~ 5,0 оC in summer, ΔT ~ 0,5 оC in winter). This process provides additional energy for sinking of warm and salt mixed water in summer, when it penetrates far into the Arctic. In winter, the temperature difference between the mixing waters is about zero, so the cabbeling almost disappears. Both temperature and salinity have climatic trends in the Chukchi Sea that causes the climate-scale variation of the cabbeling: its impact increases in 0.002 kg/m3 per decade in summer because of climatic heating (~0,13 оC/decade) and salinity decrease (~0.04 psu/decade).

The mountain cryosphere is crucial for socio-economic processes, especially during the dry seasons. However, anthropogenic climate change has had a detrimental impact on the cryosphere due to its sensitivity. Over the past two decades, there has been a decline in precipitation and a temperature rise, leading to a substantial reduction in the timing and extent of snow cover. This increase in temperature also elevates the snow line elevation (SLE), further diminishing the volume of available freshwater in the snow-driven basins of the Andes. In this study, we use 22 years (2000–2021) of 8-day snow product (MOD10A2) from the Moderate Resolution Imaging Spectroradiometer (MODIS) to analyze the annual and seasonal variability of snow cover area, SLE, and snow persistence (SP, an indicator of the duration of snow) in the Yeso River basin in Central Chile and the correlation of SP and SLE with hydrometeorological variables and climatic indices. We introduce a new approach called the Maximum Dissimilarity Method to obtain the SLE even on cloudy days. The results are as follows: (1) Snow cover area reductions of 34.0 km2 at low elevations in spring and 86.5 km2 at mid elevations in summer were found when comparing the period 2016–2021 to 2000–2004; (2) SP trends at the annual scale revealed a significant decrease in 89% of its area and an average of 3.6 fewer days of snow cover per year; (3) an upward and significant trend of 21 m‧year−1 in the annual SLE was found; and (4) annual SP and SLE were highly correlated with annual hydrometeorological variables, and spring and summer snow variables were significantly correlated with dry streamflow. This methodology can potentially serve as a valuable tool for detecting trends in snow-covered surfaces, and thereby associate these changes with climate change or other anthropogenic effects in future research.

Variations in trend rates of annual values of the Central England Temperature series (CET) over the period1659-2017 were analysed using moving windows of different length, to identify the minimum period in which the trend expresses a climate signal not hidden by the noise produced by natural variability. Trend rates exhibit high variability and irregular shifting from positive to negative values unless very long window lengths (of 100 years or more) are used. In general, as the duration of the length of the temporal window analysed increases, the absolute range of the trend rates decreases and the signal-to-noise (S/N) ratio increases. The relationship between the S/N ratio and the window length also depended on the total length of the series, so high S/N values are achieved faster when shorter time series are considered. This prevents suggesting a minimum window length for undertaking trend analyses. A comparison between CET and the average continental series in the Berkeley Earth Surface Temperature (BEST) database in their common period (1753-2017) repeats the patterns described for 1659-2017, although the average values of the rates, ranges and the "threshold period" in years change, and are more variable in CET than in BEST. Analysis of both series suggests that the recent warming started early and can be linked to the recovery of temperatures after the Little Ice Age. This process has characterised by progressively increasing trend rates, but also includes periods of deceleration or even negative trends spanning less than 50 years. The behaviour of the two long-term temperature records analysed agrees with a long-term persistence (LTP) process. We estimated the Hurst exponent of the CET series to be around 0.72 and 0.8, which reinforces the LTP hypothesis. This implies that the currently widespread statistical framework assuming a stationary, short-memory process in which departures from the norm can be easily assessed by monotonic trend analysis should not be accepted for long climatic series. In brief, relevant questions relative to the recent evolution of temperatures such as the distinction between natural variability and departures from stationarity; attribution of the causes of variability at different time scales; determination of the shortest window length to detect a trend; and other similar ones have still not been answered and may require adoption of an alternative analytical framework.

The climatic variation of offshore wind energy has a close relationship with the long-term plan of energy utilization. However, the work on this aspect is scarce and mainly focuses on the variation of wind power density (WPD). There is little research on the climatic trends of effective wind speed occurrence (EWSO) and occurrence of energy level greater than 200 W/m2 (rich level occurrence, RLO), which are directly related to the available rate and richness of wind energy. Based on the ERA-Interim wind product from the ECMWF, this study calculated the climatic trends of series of key factors of wind energy in the global oceans, including the WPD, EWSO, and RLO. The results show that the wind energy exhibits a positive trend globally for the past 36 years, with overall annual increasing trends in WPD, EWSO, and RLO, of 0.698 (W/m2)/yr, 0.076%/yr, and 0.090%/yr separately. The annual trend exhibits evident regional differences. The areas with significant increasing trends are mainly distributed in the mid- low-latitude waters of global oceans and part of the southern hemisphere westerlies. The annual increasing trend of WPD is strongest in the southern westerlies, especially in the extratropical South Pacific (ETSP), of about 1.64 (W/m2)/yr. The annual increasing trends of EWSO and RLO are strongest in the tropical waters, especially the tropical Pacific Ocean (TPO), of 0.17%/yr and 0.19%/yr separately. The annual and seasonal WPD, EWSO, and RLO in most global oceans have significant increasing trends or no significant variation, meaning that the wind energy trends are rich or stable, which is beneficial for energy development. The climatic trends of wind energy are dominated by different time periods. There is no evident abrupt change of wind energy in the extratropical waters globally and tropical Atlantic Ocean (TAO). The abrupt periods of wind energy in the TIO and TPO occurred in the end of the 20th century and the beginning of the 21st century. The wind energy of the South China Sea, Arabian Sea, and the Bay of Bengal and nino3 index share a common period of approximately 5 years. The offshore wind energy was controlled by an oscillating phenomenon.

Extreme precipitation (EP) events are life‐threatening phenomena that are expected to continue to increase because of ongoing climate change. In the past decade, these events have been caused by important and well‐documented variations in large‐scale atmospheric circulation. Identifying the trends, dynamics, and related causes of EP could help in recognizing geographical areas that are at great risk and reducing their adverse impacts, particularly on a relatively small area such as the Italian peninsula. The relationships between large‐scale circulation types (CTs) and EP were investigated using a long time‐series (1979–2015) of meteorological data recorded by 46 weather stations in Italy. EP was defined as the number of days with accumulated precipitation above the 90th percentile (R90p). The seasonal trends of R90p were not homogeneous and showed significant increases primarily in winter and spring. Only a few CTs were significantly related to R90p, and this relationship was strongly dependent on latitude, orographic exposure, and season. Heterogeneous seasonal trends for daily CT occurrences were also observed. 'Cyclonic' CTs grouped together showed significant increasing trends in all seasons, whereas 'Anticyclonic' ones showed a generalized decreasing trend, explaining, only partially, the increase of R90p observed in some stations. Meanwhile, the R90p trends seem to be more influenced by the variations in the internal characteristics of CTs (i.e., the variation of some meteorological parameters that characterize them) observed over the past few decades than by changes in CT frequencies but still with high heterogeneity in Italy. The results of this and other similar studies can provide useful support for the implementation of mitigation and adaptation strategies to minimize the impacts of severe weather, particularly in complex areas such as the Mediterranean basin. [ABSTRACT FROM AUTHOR]

Climate change has a substantial influence on a range of meteorological factors and the global hydrological cycle. This paper presents an analysis of the annual rainfall (P), temperature (including maximum temperature: T max , minimum temperature: T min , and average temperature: T avg), stream flow (Q) data from 6 gauging sites, and groundwater level (GL) data from 7 groundwater stations in and around the Barak River Basin in India from 1986 to 2020. To identify patterns in the time series, the simple linear regression (SLR) approach, the Mann-Kendall (MK) test, the Hamid Mann-Kendall (HMK) test and the Spearman's Rho (SRO) tests have been employed. Pettit test has been used to identify the change points in the time series. The results indicated an increase in the T max and the T min across the study area, while no clear patterns were found in the T avg time series. Except for the 'Hailakhandi' station, the annual total rainfall series showed an increasing trend. T max and T min showed a directional change point between 1999 and 2005, and between 2001 and 2007, respectively, according to change point analysis. Except for two stations, overall declining trends in the annual stream flow were found. Moreover, a total of five out of seven groundwater stations indicated a rise in groundwater levels. The findings presented here offer valuable insights into the current condition of the Barak basin and emphasize the importance of implementing sustainable water management practices. • Significant impact of climate change on hydro-meteorological parameters in the study area. • A noteworthy increase in both maximum and minimum temperatures. • Overall declining trends in annual stream flow across most stations in the basin. • Groundwater stations demonstrate rising groundwater levels. [ABSTRACT FROM AUTHOR]

Climatic characteristics and convective conditions of heavy rain were analyzed based on the daily rainfall data at 6 observation stations in Fuyang and the NCEP/NCAR reanalysis data from 1962 to 2016. The results show that the heavy rain increased obviously in recent 55 years, and changed abruptly in 1989, which was also a major contributor to the increase in annual rainfall. Heavy rain occurred mainly from May to September, especially in June and July. The heavier the rain occurs in summer, the higher the heavy rain concentration index can be found. Three convective parameters including K index, precipitable water and vertical velocity at 850 hPa have been chosen based on the convection stability, wanted vapor condition and lifting condition. The threshold statistical method has been used to analyze the climatic trend and convective conditions. Compared to the climatic mean statistics, the threshold statistical method had obvious advantages in interdecadal and interannual timescale, or for abnormal years of heavy rain analysis. The threshold statistics showed that interdecadal and interannual variability of heavy rain had a good relationship with K index, precipitable water and vertical speed on 850 hPa that provide the favorable convective conditions for the heavy rain formation. However, the impacts of convective conditions on the trend of rainstorm were different from May to September during the recent 55 years.

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Wind regime at the Okhotsk Sea coast is considered on the base of anemometer data obtained by the Hydrometeorological Centre of Russia since early 1970s (vanes were used for the wind rate measurements before). Climatic-scale trends in wind direction and wind rate are revealed for the 43 years period. The wind rate has a tendency to decreasing in all seasons, in spite of seasonal change of the dominant direction, with the regime shift in the late 1980s. However, the main patterns of the atmospheric circulation over the Okhotsk Sea have changed slightly, so the direction of the prevailing winds is rather stable: weakening of the zonal wind component in winter was observed for several stations in the late 1990s - early 2000s only and insignificant weakening of the meridional (south) wind component occurred in summer.

Early blight caused mainly by Alternaria solani Soraeur and Alternaria alternata (Fr.) Keissl is one of the main diseases of potato. To improve forecasting of disease risk and to provide useful tools for a good decision support system, knowledge about the influence of environmental conditions on the Alternaria species, is necessary. The pattern distribution of the Alternaria spores during eight potato growing cycles in "A Limia" (north-west Spain), and the relationships between Alternaria levels and meteorological parameters were analyzed. Also, the phenology of the potato plants and the meteorological conditions during the study were monitored. Higher Alternaria peaks were found during plant senescence. Nevertheless, extremely high levels can appear starting the plant flowering, when the disease is more destructive. Statistical analysis showed a close relationship between temperature and relative humidity with the concentration of Alternaria in the air. Higher Alternaria levels were observed with a mean temperature above 20 °C and a mean relative humidity below 70%. It is also important to highlight that lower temperature and higher relative humidity during the night, favours the formation of Alternaria spores during the day. The present study showed how differences in weather can be related with the presence of Alternaria spores in the atmosphere of potato crop, and how climate change could affect the development of this agricultural crop. If Spain continues to experience increases in temperature events, longer duration and increasing intensity of early blight epidemics in potato crops are expected in future years. [ABSTRACT FROM AUTHOR]

Formulation of the problem. The study and assessment of air temperature fluctuations, especially in conditions of expected climate change, is of particular relevance and haste. At the same time, the assessment of temporary changes in air temperature is important as a guarantee of stable development and a long-term economic development. The purpose of the article. The purpose of this work is to find out, analyze and evaluate the patterns of the dynamic changes in air temperature in Gyumri city. To solve this problem, the results of actual observations of the air temperature of the Gyumri weather station, stored at the Ministry of Emergency Situations of the Republic of Armenia «Service for Hydrometeorology and active influence on atmospheric phenomena» have been collected, refined and analyzed. Methods. In the course of research we analyzed and clarified appropriate literary sources, using mathematical-statistical, extrapolation, complex, analyze and correlation methods. Results. A multifactorial correlation relationship was obtained between the average annual air temperature and its absolute maximum and minimum values of Gyumri city. A close correlation was also obtained between the average annual air temperature and its absolute maximum and minimum values of Gyumri city, between the average annual and extreme values of the surface air temperature and the absolute maximum and minimum values of the soil surface of Gyumri city. This makes it possible to calculate the value of any temperature characteristic, while having the other one. Note that in winter the average air temperature values do not differ much from the average soil surface temperature values. This difference grows and reaches its maximum in summer (July – August). As a result of the research, it turned out that according to the actual data on the air temperature in Gyumri city, there was a tendency for the average annual values and absolute maximum of the air temperature to rise, while the absolute minimum values showed a downward trend (in the absolute sense). That is, in the study area in the warm season, an increase in aridity is expected on climate drainage, and in the cold season – a softening. In the work we tried to define the monthly average values of air temperature in Gyumri in 2030, 2070, 2100, using the extrapolation method. The result shows that if the changing process continues, the annual average values of air temperature will increase with comparison to current normal: in 2030 – 0.09 ºC (1.37 %), in 2050 – 0.27 ºC (4.12 %), in 2070 – 0.48 ºC (7.32 %), in 2100 – 0.85 ºC (13 %). This pattern is also characteristic of other regions of the republic. Therefore, it is necessary to implement integrated measures to adapt to the effects of air temperature changes and take this into account when working out programs for social, environmental and economic development. [ABSTRACT FROM AUTHOR]

Separating out the influence of climatic trend, fluctuations and extreme events on crop yield is of paramount importance to climate change adaptation, resilience, and mitigation. Previous studies lack systematic and explicit assessment of these three fundamental aspects of climate change on crop yield. This research attempts to separate out the impacts on rice yields of climatic trend (linear trend change related to mean value), fluctuations (variability surpassing the "fluctuation threshold" which defined as one standard deviation (1 SD) of the residual between the original data series and the linear trend value for each climatic variable), and extreme events (identified by absolute criterion for each kind of extreme events related to crop yield). The main idea of the research method was to construct climate scenarios combined with crop system simulation model. Comparable climate scenarios were designed to express the impact of each climate change component and, were input to the crop system model (CERES-Rice), which calculated the related simulated yield gap to quantify the percentage impacts of climatic trend, fluctuations, and extreme events. Six Agro-Meteorological Stations (AMS) in Hunan province were selected to study the quantitatively impact of climatic trend, fluctuations and extreme events involving climatic variables (air temperature, precipitation, and sunshine duration) on early rice yield during 1981-2012. The results showed that extreme events were found to have the greatest impact on early rice yield (−2.59 to −15.89%). Followed by climatic fluctuations with a range of −2.60 to −4.46%, and then the climatic trend (4.91-2.12%). Furthermore, the influence of climatic trend on early rice yield presented "trade-offs" among various climate variables and AMS. Climatic trend and extreme events associated with air temperature showed larger effects on early rice yield than other climatic variables, particularly for high-temperature events (−2.11 to −12.99%). Finally, the methodology use to separate out the influences of the climatic trend, fluctuations, and extreme events on crop yield was proved to be feasible and robust. Designing different climate scenarios and feeding them into a crop system model is a potential way to evaluate the quantitative impact of each climate variable. [ABSTRACT FROM AUTHOR]

While glacier mass changes in the Himalaya since the year 2000 are relatively well investigated, there is still a lack of knowledge about the long-term changes and their climatic drivers. We use historical and recent remote sensing data to study glacier changes of the Lahaul-Spiti region in western Himalaya, India, over the last four decades (1971-2013). The glaciers were losing mass moderately between 1971 and 1999 (− 0.07 ± 0.1 m w.e. year−1) while the losses have increased significantly after 2000 (− 0.30 ± 0.1 m w.e. year−1). During both periods, the debris-covered glaciers and glaciers having pro-glacial lakes lost more mass than glaciers with little debris cover. Mass changes of Chhota Shigri, a benchmark glacier, closely matched the average of the overall study area. Analysis of gridded climate data covering the period 1948-2015 shows that the mean annual air temperature increased, especially since 1995. One dataset shows a significant increase in summer temperature after 2000 while others do not show any trend. The mean annual precipitation started decreasing around 1995 and reached a minimum around 2000, after which it increased again. One dataset shows a significant decrease in winter precipitation after 2000 while the others show no trend. The climate data indicate that the increase in mean annual temperature from 1995, combined with no significant trend/significant decrease of winter precipitation in the period after 2000, has probably resulted in accelerated mass loss of the glaciers. [ABSTRACT FROM AUTHOR]

The main objectives of this paper are to present the temporal climatic characteristics of precipitation and air temperature in Taubaté (SP), in addition to the characterization of the rainy season. The time trend of the climatic elements were studied using the non parametric seasonal Mann-Kendall test. Statistically, no significant average changes in precipitation were detected although a relatively large natural year-to-year variability there exits. A short-term increasing trend from 1983 to 2005 have been observed in November precipitation, a decreasing trend in the amount of the April precipitation and a decreasing trend in the number of dry days per year. This study suggests that the onset of the Taubaté's rainy season occurs in mid-September and the end is in April.

Abstract: The spatio–temporal variations of major meridional modes are studied by using the ECMWF and NCEP/NCAR reanalyzed geopotential data between 70 and 10hPa during 1979 and 2001. The variance contribution rates from the first and second modes are 56–69% and 14–22%, respectively, for ECMWF, but 76–85% and 9–10% for NCEP/NCAR. The climatic trend coefficients are positive and negative in the troposphere and stratosphere, respectively. The reversal is remarkably correlated with the AO/NAM, AAO/SAM and polar vortex, suggesting their important role in connecting the mid-low and upper circulation and the interaction between SH and NH. [Copyright &y& Elsevier]

Seven vibro-cores were collected from three shallow lakes of the Gabon (Kamalété, Nguène, Maridor) along a 300-km west-east transect close to the Equator. These lakes are located in very distinct landscapes: coastal forest-savanna mosaic, rain forest and savanna with colonising forest, respectively. Core chronologies were established by radiocarbon dating. Study of these lacustrine archives (textural variables, clay minerals, organic matter components, δC, pollen) allowed comparison of late Holocene environmental changes recorded at each site and with results from other studies. Lake Kamalété indicates minor climatic deterioration (increased drying and greater seasonality) between 1,410 and 500 cal. years BP, which is also recognised in southern Cameroon and east-central Africa. Lake Nguène was surrounded by dense moist forest throughout the last 4,110 years, but shows significant deterioration from ~2,800 cal. years BP, a phenomenon seen at nearby sites. Lake Maridor shows a decline of forest initiated a little after 3,800 cal. years BP, which indicates timing that is distinct from the two other sites. This was probably a response to local conditions (i.e. outlet damming). Although the three lakes display generally parallel climatic trends perhaps linked to SST oscillations, there is not perfect coherence between these three sites. Differences among the three basins may be attributable to local factors like groundwater hydrology and slope instabilities of such shallow lake systems in this equatorial region. [ABSTRACT FROM AUTHOR]

The condition of the ice on a large lake is an important sensitive indicator of regional climate change. We have investigated the ice regime on Lake Ladoga using aircraft surveys and satellite images. Nearly 1,000 surveys of the lake’s ice cover covering the years from 1943 to the present were analyzed to determine the first basic statistical characteristics of Ladoga ice cover based on long-term observation. The aim was to estimate long-term trends in the ice cover. Analysis showed that the average period of ice-cover formation is up to 1.5 times longer than the period of ice-cover destruction. The inter-annual trends in first and last ice dates, and in the duration of ice cover, are a few days per century, i.e. significant but rather small. We created the Relative Ice Cover Index (RICI), a dimensionless single-number variable that allowed the characteristics of winter seasons to be compared. A statistically significant downward trend of no more than 12% in RICI was observed over the 63-winter periods. The distribution of RICI was compared with the North Atlantic Oscillation Index (NAO) in an effort to explain the ice cover trend. [ABSTRACT FROM AUTHOR]

Trends of annual and monthly temperature, precipitation, potential evapotranspiration and aridity index were analyzed to understand climate change during the period 1971–2000 over the Tibetan Plateau which is one of the most special regions sensitive to global climate change. FAO56-Penmen-Monteith model was modified to calculate potential evapotranspiration which integrated many climatic elements including maximum and minimum temperatures, solar radiation, relative humidity and wind speed. Results indicate generally warming trends of the annual averaged and monthly temperatures, increasing trends of precipitation except in April and September, decreasing trends of annual and monthly potential evapotranspiration, and increasing aridity index except in September. It is not the isolated climatic elements that are important to moisture conditions, but their integrated and simultaneous effect. Moreover, potential evapotranspiration often changes the effect of precipitation on moisture conditions. The climate trends suggest an important warm and humid tendency averaged over the southern plateau in annual period and in August. Moisture conditions would probably get drier at large area in the headwater region of the three rivers in annual average and months from April to November, and the northeast of the plateau from July to September. Complicated climatic trends over the Tibetan Plateau reveal that climatic factors have nonlinear relationships, and resulte in much uncertainty together with the scarcity of observation data. The results would enhance our understanding of the potential impact of climate change on environment in the Tibetan Plateau. Further research of the sensitivity and attribution of climate change to moisture conditions on the plateau is necessary. [ABSTRACT FROM AUTHOR]

This study analyzed the variability of rainfall and temperature in southwest coastal Bangladesh and assessed the impact of such variability on local livelihood in the last two decades. The variability analysis involved the use of coefficient of variation (CV), standardized precipitation anomaly (Z), and precipitation concentration index (PCI). Linear regression analysis was conducted to assess the trends, and a Mann–Kendall test was performed to detect the significance of the trends. The impact of climate variability was assessed by using a livelihood vulnerability index (LVI), which consisted of six livelihood components with several sub-components under each component. Primary data to construct the LVIs were collected through a semi-structed questionnaire survey of 132 households in a coastal polder. The survey data were triangulated and supplemented with qualitative data from focused group discussions and key informant interviews. The results showed significant rises in temperature in southwest coastal Bangladesh. Though there were no discernable trends in annual and seasonal rainfalls, the anomalies increased in the dry season. The annual PCI and Z were found to capture the climate variability better than the currently used mean monthly standard deviation. The comparison of the LVIs of the present decade with the past indicated that the livelihood vulnerability, particularly in the water component, had increased in the coastal polder due to the increases in natural hazards and climate variability. The index-based vulnerability analysis conducted in this study can be adapted for livelihood vulnerability assessment in deltaic coastal areas of Asia and Africa. [ABSTRACT FROM AUTHOR]

Under the control of geographical environment and the influence of modified west air mass, the mass balance of glaciers in the Tianshan Mountains has continously decreased since the 1970s. However, the lake level has increased gradually duo to the increase of precipitation. The interaction between temperature and precipitation resulted in a normal and slightly more total amount of water resources in the areas of the Tianshan Mountains. It is estimated that this climatic trend will last to the early stage of the next century. [ABSTRACT FROM AUTHOR]

• Durum wheat suitability under no till (NT) management is determined by aridity index. • Distinct aridity index thresholds were considered in relation to cropping management. • Climate uncertainty is the major driving to NT adoption. • The probability of NT success is affected by cropping systems and residue management. • Sicilian climatic trend determines an increase of the areas suitable for NT. In the field of conservative agriculture, no-till (NT) management has been receiving increasing interest, with 45 million ha of land under no-till management in 1999 to 155 million ha in 2014. Up until now, no-till has only been observed to perform better under rainfed conditions, especially in dry climates mainly because the reduced tillage system retains more soil moisture. However, the adoption of alternative agricultural practices (NT) can be improved only if uncertain and consequent assumption of risk is well known and accepted. For these reasons, the aim of this research is (i) to define durum wheat suitability under NT soil management in terms of yield success probability and (ii) to determine the suitable area for NT wheat cultivation within three climatic periods (the past, present, and future). The probability distribution of the aridity index (AI) was used to derive the non-exceedance conditional probability of NT yield success in comparison to conventional tillage (CT) on arable land in the Sicilian Region (southern Italy). The probability of NT management resulting in a higher yield than CT management for each specific environment was predicted. The latter made it possible to determine the probability of a higher yield under NT practice in comparison to CT, considering both the environment (aridity index) and different management practices (cropping system and residue management). An analysis of the relationship between the crop yield and the AI showed that the probability of NT success in durum wheat yield is affected by cropping systems and residue management and that Sicilian climatic trends will determine an increase in the areas suitable for NT durum wheat management. The uncertainty quantification or the success yield probability of NT could be used to target incentives for NT durum wheat cultivation in areas (within a region) where the mean yield and non-exceedance probability are low. [ABSTRACT FROM AUTHOR]