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Barkan investigated the synoptics of dust trajectories to Europe, Arctic, E. & W. Mediterranean, and the Atlantic Ocean (Barkan et al. 2004). His most recent research just before he passed away Barkan studied the outstanding Red Snow Event in Eastern Europe on March 2018. In April 2018 the European media published in great headlines a strange occurrence. Red colored snow fell in Bulgaria, Rumania, Ukraine and what was most interesting to the media, was reported in the mountains around Sochi the location of the former winter Olympic Games. Barkan showed that the phenomenon of the red snow in southwestern Europe is the result of a cold trough which penetrated from the north toward the central Mediterranean and Saharan Africa, together with its movement eastward. Consequently, a strong southwesterly flow formed along the eastern flank of the trough. This flow transported a large amount of red Saharan dust which upon mixing with the snowfall in the area painted the snow red (Barkan and Alpert, 2020). In this case the trough developed further east which is not a common occurrence. This has caused heavy dust storms in central Sahara near the most ample dust sources (Barkan, Kutiel and Alpert, 2004). So, it will be shown that the transported dust reached the area together with snow flakes and probably painted it in red or brown.Another interesting study by late Barkan is on the difference in the synoptic situation between years with a large amount of dust and years with relatively small amount, in the Sahara- this was examined for 1979-1992 (Barkan and Alpert, 2008). For every month the dustiest and the non-dustiest year were chosen and the average of the three months in the season of these years was examined. The examination was made for the atmospheric variables: wind flow, wind velocity, geopotential height and temperature, at the 700 hPa level. The data used were the daily aerosol index from the TOMS satellite born instrument and the daily NCEP/NCAR reanalysis data of the variables mentioned above between the years 1979-1992. Other interesting studies will be reviewed including, a novel climatic index for the total Saharan dust being discovered as the Sun insolation; a unique case-study of near-circular Saharan dust transport over the Atlantic Ocean; and dust as a potential tracer for the flow over different topographical shapes employing MODIS-Terra observations.References:Barkan, P. Kishcha, H. Kutiel, and P. Alpert, "The Synoptics of Dust Intrusion Days from the African Continent into the Atlantic Ocean", J. Geophys. Res., Vol. 109, No. D8, D08201=2010.1029/2003JD004416=20, 2004. Barkan, H. Kutiel and P. Alpert, "Climatology of dust sources over the North African region, based on TOMS data", Indoor-Built Environ., Vol. 13, 407-419, 2004. Barkan, P. Alpert, H. Kutiel, and P. Kishcha,"The Synoptics of dust transportation days from Africa toward Italy and Central Europe", J. Geophy. Res., 110, doi:10.1029/2003 JD004416, 2005. Alpert, J. Barkan, and P. Kishcha, "A potential climatic index for total Saharan dust: the Sun insolation", J Geophy. Res., 111, D01103, doi:10.1029/2005JD006105, 2006.

The near-surface humidity is a crucial variable in many atmospheric processes, mostly in those related to development of clouds and rain. The humidity at the height of a few tens of meters above surface is highly influenced by the surface characteristics. In many cases the land-cover (LC) is responsible for the spatial variation of the surface humidity field, therefore, it is a major factor in determining the conditions for rainfall. Cities are one of the primary LCs which have a substantial impact on the humidity field. Large urban areas are expanding, causing a significant change in the near-surface humidity field. Measuring the near-surface humidity in high resolution, where most of the humidity’s sinks and sources are, is challenging with the common tools available today. Current measurement tools do not satisfactorily assess the cities’ effects on the humidity field. A new approach for measuring the humidity, based on the cellular network, provides high resolution information on the near-surface humidity. Therefore, we can examine the land-cover effect on the humidity in the low atmosphere in fine scale. In this study, the humidity field around Tel Aviv was retrieved from the cellular network during the summer of 2017. The results show a well-noticed impact of the city and other LC types on the humidity field over the Tel Aviv metropolitan area. The method presented here can offer an improved description of the humidity field at the city-canopy level and therefore provide a better assessment of the urban/LC effects on the environment, atmospheric modeling, and particularly on clouds/rain development.

Climate change phenomena represent the most serious threats to human well-being and sustainable development. This affects several dimensions of human life from individual health issues to economic growth, passing through civil protection, with strong impacts on European territories and in several other world regions. The I-CHANGE (Individual Change of HAbits Needed for Green European transition, 2021-2025) project faces the challenge of engaging and promoting the active participation of citizens (students, cultural associations, cyclists, boat men etc) for addressing climate change, sustainable development and environmental protection in the framework of the European Green Deal , the European Climate Pact and the European Biodiversity Strategy for 2030.The overall driving concept is that citizens and civil society have a central role in the definition of environmental protection and climate action and their direct involvement is essential to drive a true shift and promotion of changes of behaviors towards more sustainable patterns. I-CHANGE represents a change of paradigm achievable through a multidisciplinary and participatory approach: improvement of data usability - citizen understanding raises through the observation of the environmental impacts of human activities; active participation of citizens - the active involvement of citizens through a set of Living Labs (LLs) located in different socio-economic contexts (Europe, Middle-East and Africa); climate change awareness – the development of clear understanding for citizens of the scientific processes underlying climate change and environmental protections; behaviour change – addressing the climate crisis requires a focus on high-impact behaviours and high-emitting groups. First year and half of I-CHANGE activities will be presented and discussed.

Jerusalem City is unique in its diversity of populations with atotal of 936,000 inhabitants (end of 2018) with 62% Jewish and 38% Arabs,and is located exactly at the border of Mediterranean climate with a significantvariability between the coastal area, including Jerusalem City (annual rainfall~600 mm) and the most arid zone of the Dead Sea, 20-30 km east of the city(annual rainfall ~50 mm). The spatial-temporal variation of rainfallintensity is the main and not well-known driver that generates the majority of flash floods in the nearby Judean Desert. Hence, its monitoring is crucial in this area as in other remote arid areas worldwide. Recently, extensive research was performed related to global warming potential risks and their effects on rainfall and temperature over the East Mediterranean. Several major risks were pointed out including extreme temperatures, heat waves, colder nights and heavy rainfall. Important to notice is our first super-high-resolution global climate model projections that the ancient “Fertile Crescent” in the Middle East (considered as the cradle of civilization), will nearly disappear during this century by the year 2100 (Kitoh et al. 2008). Jerusalem temperatures both maximum and minimum show that significant increases occurred during 1950-2020 (based on homogenized dataset, Yosef et al., 2019). Furthermore, enhanced increases are shown to have occurred from the 1980s of the temperature trends which are even more than double of the global average ones. A fact that led to definition of the Mediterranean as a “Hot Spot” of global warming. Comparison of Jerusalem temperatures increasing trends to the coastal upstream Bet Dagan station, at ~40 km to the west does show similar patterns of statistically most significant increases in the region as well as large inter-annual variabilities. A general reduction in the annual amount was observed in the last four decades over Jerusalem. This tendency is expected to continue and become more pronounced under the "business as usual" scenario of RCP8.5. Some potential socioeconomic impacts will be presented.

Climate change phenomena represent the most serious threats to human well-being and sustainable development. This affects several dimensions of human life from individual health issues to economic growth, passing through civil protection, with strong impacts on European territories and in several other world regions. The I-CHANGE (Individual Change of HAbits Needed for Green European transition, 2021-2025) project faces the challenge of engaging and promoting the active participation of citizens for addressing climate change, sustainable development and environmental protection in the framework of the European Green Deal , the European Climate Pact and the European Biodiversity Strategy for 2030. The overall driving concept is that citizens and civil society have a central role in the definition of environmental protection and climate action and their direct involvement is essential to drive a true shift and promotion of changes of behaviors towards more sustainable patterns. I-CHANGE represents a change of paradigm achievable through a multi-disciplinary and participatory approach: improvement of data usability - citizen awareness raises through the observation of the environmental impacts of human activities; active participation of citizens - the active involvement of citizens through a set of Living Labs (LLs) located in different socio-economic contexts (Europe, Middle-East and Africa); climate change awareness - the development of clear understanding for citizens of the scientific processes underlying climate change and environmental protections. First year of I-CHANGE activities will be presented and discussed.

The trend of the decrease in the global average diurnal temperature range (DTR) is one of the clearest signals in twentieth century climate data. Regionally, DTR trends exhibit large variations. A factor separation analysis was conducted to investigate the impact of atmospheric moisture, synoptic‐scale winds, and their synergy on the DTR during the Israeli summer. The Weather Research and Forecasting (WRF) Single Column Model was run for summer representative days, at four locations in Israel. In almost all cases, the contribution of the factors and of their synergy to the DTR was dominated by their contribution to the diurnal minimum temperature, Tmin. The largest contribution resulted from atmospheric moisture, reducing the DTR. The contribution of synoptic‐scale winds showed more variability, with significant differences in both magnitude and sign on different days. The sign of the effect on Tmin depended on the relative direction and magnitude of the nocturnal synoptic‐scale wind with respect to the local wind, which in turn determined the effect on the low‐level jet (LLJ) and vertical mixing. The contribution from synergy between the two factors depended on the effect of moisture on the LLJ and on the effect of the synoptic‐scale winds on moisture advection in or out of the atmospheric column. All cases were classified into groups depending on the sign of contributions of the single factors and of their synergy when analyzing the DTR observed trends. These results highlight the importance of the synoptic wind, of its synergy with atmospheric moisture and of the feedback mechanisms.

Risks associated with public health have no borders, as the recent Corona virus (COVID-19) pandemic developing during the course of the workshop,clearly demonstrated. Thus,the challenges climate change pose to society and especially to public health can only be properly met with inter-disciplinary regional collaborations. In January 27-28, 2020, the Eastern Mediterranean Regional Climate Change Adaptation Center (RCCAC) conducted a successful workshop hosted by the Abdus Salam International Center for Theoretical Physics in Trieste, Italy. This workshop initiated the cooperation of a regional community of climate, public health and policy scientists to collaborate on the health-related aspects of climate change in the Eastern Mediterranean. Scientists from Jordan, the Palestinian Authority, Israel, Cyprus, Germany and Italy participated and presented their state-of-the-art disciplinary research. The outcomes of the workshop laid the ground for close interdisciplinary regional collaboration, which will benefit the people of this vulnerable region.

In the last decade, commercial microwave links (CMLs) have been treated as opportunistic near-ground rain sensors, and successfully used for the retrieval of 2-D near-ground rain fields in several countries. In spite of the path integration of a CML, most studies represent the rainfall measured by a CML as a single virtual rain gauge (VRG) in the center of the path. Here, we study the performance of spatial reconstruction of rain fields by an inverse distance weighting (IDW) spatial interpolation method. We compare the case where each CML is represented by a single VRG with the case where it is represented by several VRGs along its path. A synthetic rain field was produced, simplified to a single rain cell, and sampled by a synthetic CML network that was built according to statistics of actual CMLs. A Monte Carlo simulation study yielded a quantitative and specific set of metrics showing that the rain-retrieval results are scenario-dependent and can be used to design a rain-retrieval system. In particular, we show that if the rain-cell dimensions are in the order of the average length of the CMLs, using several VRG with the iterative algorithm can significantly improve the retrieval performance, whereas the performance gain is small otherwise.

The “Teleconnection” term in climate studies was defined primarily for widely separated regions. This stems from the basic idea that a physical process, such as an advection or a particular synoptic system, cannot simply explain a relation or a correlation in large distances. Also, in modern times, models more often fail in predicting these remote patterns, particularly with regional models, such as in the hurricane example and its effect on Mediterranean precipitation, explored here. Several teleconnection relations are reviewed, with particular focus on Mediterranean rainfall. It is argued that even with a clear physical process of advection and for a short horizontal scale, ‘teleconnection’ is often not well understood, if the physical mechanism involved is complex, such as in the sub-synoptic scales of aerosol-rainfall interaction or megacities and their potential effects on precipitation. Thus, a broader look at the horizontal scale of teleconnection is proposed where the word TELE is still representing the word ‘far’, as in its Greek origin, but it also includes our limitation in understanding of complex atmospheric relations in various distances.Furthermore, the hidden assumption that ancients were not able to observe teleconnections is contradicted by an example from ~1800 years ago. In this example, a claim was made in the Talmud that the Euphrates flow is strongly related to the rainfall over the greater Israel region, located at ~700-900 km westward. However, the understanding of this ancient teleconnection was only possible at the 2nd half of the 19th century when the role of synoptic systems in weather, has emerged. Keywords: Teleconnection, Rainfall, synoptic system, Euphrates discharge, Middle East, Levant, Talmud REFERENCE:P. Alpert and H. Saaroni, “Historical and New Insights into Atmospheric Teleconnection” Oxford Research Encyclopedia of Climate Science (eds von Storch, H. et al.) (Oxford Univ. Press, Oxford, 2021).(accepted Aug. 2021)

In the summer months, characterized by the absence of precipitation and by limited cloud cover, subtropical lakes are particularly sensitive to atmospheric warming which causes increasing heating of surface water. Therefore, these lakes are best suited to the investigation of this phenomenon.Within the Jordan Rift valley there are two lakes: the fresh-water Lake Kinneret (Sea of Galilee) (a surface area of 106 km2 and a maximal depth of 40 m) and the hypersaline Dead Sea (a surface area of 605 km2 and a maximal depth of 300 m). We investigated water surface temperature (WST) and its trends in the two lakes. This was carried out using MODIS 1 km x 1 km resolution records on board Terra and Aqua satellites together with in-situ measurements, during the period (2003 – 2019). In fresh-water Lake Kinneret, we found that, in summer when evaporation is maximal, despite the presence of increasing atmospheric warming, satellite data revealed the absence of WST trends (Kishcha et al., 2021). The absence of WST trends in the presence of increasing atmospheric warming is an indication of the influence of steadily increasing evaporation on WST. Increasing water cooling, due to steadily increasing evaporation, compensated for increasing heating of surface water by regional atmospheric warming. This resulted in the obtained statistically-insignificant WST trends. During the study period (2003 – 2019), in summer, in contrast to satellite data, in-situ measurements of near-surface water temperature (at a depth of 0.1 m) in Lake Kinneret showed an increasing trend of 0.7 oC decade-1. This trend in near-surface water temperature reflected the presence of increasing atmospheric warming in the absence of evaporation.In contrast to fresh-water Lake Kinneret, in the hypersaline Dead Sea (located only 100 km apart), MODIS showed an increasing statistically-significant trend of 0.8 oC decade-1 in summer WST. This fact was obtained during the same study period (Kishcha et al., 2021). The increasing WST trend, in the presence of atmospheric warming, is evidence of the absence of increasing evaporation in the Dead Sea. This fact is supported by a constant rate of ~1 m/year of Dead Sea water level drop during the last 25-year period (1995 – 2020). The absence of increasing evaporation could be explained by surface water salinity in the Dead Sea skin layer. Increasing surface water salinity suppresses further increases in evaporation. As a result, there was no acceleration in Dead Sea water level drop in the presence of an increasing SWT trend of 0.8 oC decade-1. We consider that this is a characteristic feature of the hypersaline Dead Sea, which is not present in the fresh-water Lake Kinneret.Reference:Kishcha et al. (2021). Absence of surface water temperature trends in Lake Kinneret despite present atmospheric warming: Comparisons with Dead Sea trends. Remote Sensing, 13, 3461. https://doi.org/10.3390/rs13173461

This study was carried out using Moderate Resolution Imaging Spectroradiometer (MODIS) 1 km × 1 km resolution records on board Terra and Aqua satellites and in-situ measurements during the period (2003–2019). In spite of the presence of increasing atmospheric warming, in summer when evaporation is maximal, in fresh-water Lake Kinneret, satellite data revealed the absence of surface water temperature (SWT) trends. The absence of SWT trends in the presence of increasing atmospheric warming is an indication of the influence of increasing evaporation on SWT trends. The increasing water cooling, due to the above-mentioned increasing evaporation, compensated for increasing heating of surface water by regional atmospheric warming, resulting in the absence of SWT trends. In contrast to fresh-water Lake Kinneret, in the hypersaline Dead Sea, located ~100 km apart, MODIS records showed an increasing trend of 0.8 °C decade−1 in summer SWT during the same study period. The presence of increasing SWT trends in the presence of increasing atmospheric warming is an indication of the absence of steadily increasing evaporation in the Dead Sea. This is supported by a constant drop in Dead Sea water level at the rate of ~1 m/year from year to year during the last 25-year period (1995–2020). In summer, in contrast to satellite measurements, in-situ measurements of near-surface water temperature in Lake Kinneret showed an increasing trend of 0.7 °C decade−1.

The Mediterranean region is projected to be significantly affected by climate change through warming and drying. The Eastern Mediterranean (EM) is particularly vulnerable since the bulk of the prec ...

The penetration of the uniquely strong Mediterranean Sea Breeze (MSB) into the Dead Sea (DS) valley has been studied for decades. However, the studies relied mostly on surface observations and coarse-model simulations. Motivated by the significant interdaily variability, we investigate two typical but different events: a frequent event in which the surface specific humidity (SH) steeply decreases and surface temperature increases during MSB penetration by ~40% and 1.2 °C, respectively; and a less frequent event, with almost the opposite behavior, an increase of surface SH by ~20%. Decrease in the integrated water vapor (IWV) content at MSB arrival is significantly larger in the first event. To reveal the factors responsible for these different behaviors we use high-resolution in–situ and remote-sensing observations, together with WRF simulations. It was found that foehn developed following the MSB descent down to the DS valley and the weakening of opposing upward winds. The foehn characteristics were influenced by the synoptic and mesoscale conditions. While on the first event the foehn reached the surface of the valley, on the second it did not. This led to the different behavior of the surface temperature and SH. An additional factor was the amount of moisture brought by the DS breeze and MSB. Different altitudes of stable layers led to the different changes of the IWV. Our simulations suggest the feasibility of forecasting foehn and sudden changes in surface variables in the DS valley 24 h in advance. These forecasts can be most valuable during high pollution events.

The contributions of twelve independent factors/variables to the magnitude of the local diurnal temperature range (DTR) in Israel were examined, and five to seven were found to contribute significantly. Israel was chosen due to its complex terrain with several climatic zones and proximity to the Mediterranean Sea. The seven sites for this study represent different terrains, from mountainous with a Mediterranean climate to desert. Each site had 6 years of data available. Stepwise analysis was performed in order to determine the contribution of each factor/variable at each site. The linear correlations between the DTR and each factor were calculated. These were carried out at each site for the whole year and for each season, separately. Relative humidity was found to have the largest DTR contribution at all sites, for 3 seasons, except summer at shoreline sites and in Jerusalem. The daily cloud cover and the wind speed had small contributions in most sites. The magnitude of the DTR was found to vary largely with location and to be considerably smaller in the seashore sites than those inland.

The atmospheric greenhouse effect and the hydrological cycle of Earth are key components enabling the planet to support life. Water vapor is a central element in both of these, accounting for approximately half of the present day greenhouse effect, and comprising the most important gaseous source of atmospheric infrared opacity. Specifically, it functions as the fuel for the development of convective storm clouds. This parameter, however, is considered one of the least studied due to the limitations of conventional monitoring instruments. The current predominate monitoring tools are humidity gauges and satellites which suffer from a lack of spatial representativeness and difficulties in measuring at ground level altitudes, respectively. This study demonstrates the potential to reconstruct the 2-Dimensional humidity field using commercial microwave links which form the infrastructure for data transmission in cellular networks. Water vapor attenuates the waves transmitted by the system and thus these microwave links can potentially form as a virtual network for monitoring the humidity field. The results show a correlation of between 0.79 and 0.93 with root mean square differences ranging from 1.78 to 2.92 g/m3 between conventional humidity gauges and the humidity estimates calculated for the same points in space by the proposed technology. The results obtained are the first to point out the improved performance of humidity measurements when using data from multiple microwave links. These outcomes indicate the tremendous potential of this novel approach for improving the initialization of meteorological forecasting models thus potentially improving the ability to cope with the dangers associated with extreme weather.

The atmospheric dynamics in the Dead Sea (DS) Valley has been studied for decades. However, the studies relied mostly on surface observations and simple coarse-model simulations, insufficient to elucidate the complex flow in the area. I will present a first study using high resolution (temporal and spatial) and sophisticate both, measurements and modeling tools. We focused on afternoon hours during summer time, when the Mediterranean Sea (MS) breeze penetrates into the DS Valley and sudden changes of wind, temperature and humidity occur in the valley.An intense observations period , including ground-based remote sensing and in-situ observations, took place during August and November 2014. The measurements were conducted as part of the Virtual Institute DEad SEa Research Venue (DESERVE) project using the KITcube profiling instruments (wind lidars, radiometer and soundings) along with surface Energy Balance Station. These observations enabled analysis of the vertical profile of the atmosphere at one single location at the foothills of Masada, about 1 km west of the DS shore.High resolution (1.1 km grid size) model simulations were conducted using the WRF model. The simulations enabled analysis of the 3D flow at the DS Valley, information not provided by the observations at a single location. Sensitivity tests were run to determine the best model configuration for this study.Our study shows that foehn develops in the lee side of the Judean Mountains and DS Valley in the afternoon hours when the MS breeze reaches the area. The characteristics of the MS breeze penetration into the valley and of the foehn (e.g. their depth) and the impact they have on the boundary layer flow in the DS Valley (e.g. the changes in temperature, humidity and wind) are conditioned to the daily synoptic and mesosocale conditions. In the synoptic scale, the depth of the seasonal trough at sea level and the height of inversion layers play a significant role in determining the breeze and foehn characteristics. In the mesoscale, the intensity of the DS breeze and the humidity brought by it determines the outcomes at the time of MS breeze penetration and foehn development. Dynamically, the foehn is associated with a hydraulic jump.Hypothetical model simulations with modified terrain and with warmer MS surface temperature were conducted to reveal the relative contribution of each of these factors and of their synergism on the observed phenomena. The information provided by the factor separation study can be useful in future climate projections, when a warmer MS is expected.The forecasting feasibility of foehn and the sudden changes in the DS valley 24 hours in advance using WRF is suggested following the present study. These forecasts can be most valuable for the region affected by pollution penetration from the metropolitan coastal zone.

Over a billion people currently live in coastal areas, and coastal urbanization is rapidly growing worldwide. Here, we explore the impact of an extreme and rapid coastal urbanization on near-surface climatic variables, based on MODIS data, Landsat and some in-situ observations. We study Dubai, one of the fastest growing cities in the world over the last two decades. Dubai's urbanization centers along its coastline – in land, massive skyscrapers and infrastructure have been built, while in sea, just nearby, unique artificial islands have been constructed.Studying the coastline during the years of intense urbanization (2001-2014), we show that the coastline exhibits surface urban heat island characteristics, where the urban center experiences higher temperatures, by as much as 2.0°C and more, compared to the adjacent less urbanized zones. During development, the coastal surface urban heat island has nearly doubled its size, expanding towards the newly developed areas. This newly developed zone also exhibited the largest temperature trend along the coast, exceeding 0.1°C/year on average.Overall, we found that over land, temperature increases go along with albedo decreases, while in sea, surface temperature decreases and albedo increases were observed particularly over the artificial islands. These trends in land and sea temperatures affect the land-sea temperature gradient which influences the breeze intensity. The above findings, along with the increasing relative humidity shown, directly affect the local population and ecosystem and add additional burden to this area, which is already considered as one of the warmest in the world and a climate change 'hot spot'. References:E. Elhacham and P. Alpert, "Impact of coastline-intensive anthropogenic activities on the atmosphere from moderate resolution imaging spectroradiometer (MODIS) data in Dubai (2001–2014)", Earth’s Future, 4, 2016. https://doi.org/10.1002/2015EF000325E. Elhacham and P. Alpert, "Temperature patterns along an arid coastline experiencing extreme and rapid urbanization, case study: Dubai", submitted.

The Dead Sea is a terminal hypersaline lake at a unique location at ~430 m below sea level. Over the last several decades the Dead Sea has been drying up due to climate change: its water level has dropped at the rate of ~1 m year-1. In this study we investigated the diurnal cycle of spatial heterogeneity in Dead Sea surface temperature (SST) using METEOSAT geostationary satellite data (2005-2015). METEOSAT data showed that, in the summer months, SST peaked at the same time, 13 LT (local time), as land surface temperature (LST) over surrounding land areas. In the presence of water mixing, the maximum of SST should be observed several hours later than that of LST due to thermal inertia of bulk water. The fact that SST and LST peaked at the same time, 13 LT, is evidence that there was no noticeable vertical water mixing. We consider that, in the absence of noticeable water mixing and under uniform solar radiation in the summer months, inhomogeneity in evaporation was the main causal factor of the observed spatial heterogeneity in Dead Sea SST. METEOSAT showed that spatial heterogeneity in SST was pronounced throughout the daytime. In summer, SST peaked at 13 LT, when SST reached 38.1 oC, 34.1 oC, and 35.4 oC being averaged over the east, middle and west parts of the lake, respectively. The above mentioned spatial heterogeneity in daytime SST caused a pronounced asymmetry in land surface temperature between land areas adjacent to the east and west sides of the lake. Maximal evaporation (causing maximal surface water cooling) took place at the middle part of the Dead Sea, while minimum evaporation took place at the east side of the lake. In the nighttime, METEOSAT data showed that SST values were minimal and SST spatial distribution was much more uniform compared to the daytime. We found that, in winter, when maximal solar radiation reached ~500 W/m2 compared to ~900 W/m2 in summer, daytime SST non-uniformity was less pronounced than that in summer. As the characteristic feature of the diurnal cycle, SST daily temperature range was equal to 7.2 °C, 2.5 °C, and 3.8 °C over the east, middle and west parts of the Dead Sea, respectively, in summer, compared to 5.3 °C, 1.2 °C, and 2.3 °C in winter.Evaporation causes significant drying up of the Dead Sea, especially in the summer months, as the main contributor to maximal water level drop in the lake. However, no measurements of spatial distribution of Dead Sea evaporation have ever been conducted, either in situ or from space. Our findings allowed us to visualize spatial inhomogeneity in evaporation using the obtained heterogeneity in Dead Sea SST.Reference: Kishcha P. and Starobinets B. (2021). Spatial heterogeneity in Dead Sea surface temperature associated with inhomogeneity in evaporation. Remote Sensing (Special Issue: Remote Sensing of Lake Properties and Dynamics), 13(1), 93; https://doi.org/10.3390/rs13010093.

Keywords:Scavenging process, Rainfall, Aerosols, Lag correlation, Rainfall-aerosol processesAbstractRainfall and aerosols play major roles in the Earth climate system and substantially influence our life. Here, the focus is on the local near-surface aerosol/rainfall correlations with time-scales of minutes to days. We investigated 29 experiments including 14 specific rain events, with time resolutions of daily and 60, 30, 10 minutes at ten stations in Israel and California. The highest negative correlations were consistently at a positive lag of about 140-160 minutes where a positive lag means that the aerosol time-series follows that of the rain. The highest negative value is suggested to be the probable outcome of immediate scavenging along with the rise in aerosol concentration after rain depending on aerosol sources, hygroscopic growth and transport. The scavenging dominance is expressed by the mostly negative lag-correlation values in all experiments. In addition, the consistent lack of significant correlation found at negative lags suggest a weak aerosol effect on precipitation (Gryspeerdt et al., 2015).Plain Language Summary: Rainfall and atmospheric particles (aerosols) play significant roles in the Earth atmosphere and largely influence our weather and climate. The relations between near-surface aerosol and rainfall on time scales of minutes to days are studied, employing correlations in 10 meteorological stations in Israel and California. The highest negative correlations were consistently at a positive lag of about 140-160 minutes. A positive lag means that the aerosol time-series follows that of the rain. The highest negative correlation value is suggested to be the outcome of scavenging along with the rise in aerosol concentration after rain depending on the sources of aerosols, hygroscopic growth and transport. Furthermore, our approach provides a more fundamental insight into the local, near-surface rain-aerosol interactions, in contrast to many aerosol-rainfall studies that are climatological and with the tele-connection approach (Alpert et al., 2008), which involves other processes over distances of a few km up to even large synoptic scales. Relevant References:Alpert, P., Halfon, N., & Levin, Z. (2008). Does Air Pollution Really Suppress Precipitation in Israel? Journal of Applied Meteorology and Climatology. https://doi.org/10.1175/2007jamc1803.1Barkan, J., & Alpert, P. (2020). Red Snow occurrence in Eastern Europe - A case study. Weather. https://doi.org/10.1002/wea.3644Gryspeerdt, E., Stier, P., White, B. A., & Kipling, Z. (2015). Wet scavenging limits the detection of aerosol effects on precipitation. Atmospheric Chemistry and Physics, 15(13), 7557–7570.Tsidulko, M., Krichak, S. O., Alpert, P., Kakaliagou, O., Kallos, G., & Papadopoulos, A. (2002). Numerical study of a very intensive eastern Mediterranean dust storm, 13-16 March 1998. Journal of Geophysical Research: Atmospheres. https://doi.org/10.1029/2001jd001168