nasa-gesdisc/es-publications-researchareas huggingface dataset:
Real-time measurement of outdoor workers exposure to solar ultraviolet radiation in Pretoria, South Africa (2015)

The city of Pretoria in South Africa receives considerable solar ultraviolet radiation (UVR) because of its low latitude (2235S) and relatively clear skies. Certain meteorological factors affect the amount of solar UVR that reaches the ground; the most dominant factors being stratospheric ozone, cloud cover and solar zenith angle. It is known that overexposure to solar UVR may lead to the development of adverse health conditions, the most significant being skin cancer. Outdoor workers spend a significant amount of time outside and are thus susceptible to this risk. In this case study, we estimated, for the first time, the realtime solar UVR exposure of an outdoor worker in Pretoria. Measurements were made on 27 and 28 May 2013 using a handheld ultraviolet index (UVI) meter calibrated against a science-grade biometer at the South African Weather Service in Pretoria. Personal exposure estimation was used to discern the pattern in diurnal and annual sunburn risk for the outdoor worker. Ambient UVR levels ranged from 0 UVI to 4.66 UVI and the outdoor workers potential exposure estimates regularly exceeded 80% of these levels depending on the time of day. The risk of sunburn was evident; however, actual incidents would depend on individual skin photosensitivity and melanin content, as well as sun protection used. Further research is needed to determine the personal exposure estimations of outdoor workers in other provinces in which solar UVR levels may be equally high, or higher than those in Pretoria.

Research areas: Public Health
Prevalence of microbiological contaminants in groundwater sources and risk factor assessment in Juba, South Sudan (2015)

In low-income regions, drinking water is often derived from groundwater sources, which might spread diarrheal disease if they are microbiologically polluted. This study aimed to investigate the occurrence of fecal contamination in 147 improved groundwater sources in Juba, South Sudan and to assess potential contributing risk factors, based on bivariate statistical analysis. Thermotolerant coliforms (TTCs) were detected in 66% of the investigated sources, including 95 boreholes, breaching the health-based recommendations for drinking water. A significant association (p<0.05) was determined between the presence of TTCs and the depth of cumulative, long-term prior precipitation (both within the previous five days and within the past month). No such link was found to short-term rainfall, the presence of latrines or damages in the borehole apron. However, the risk factor analysis further suggested, to a lesser degree, that the local topography and on-site hygiene were additionally significant. In summary, the analysis indicated that an important contamination mechanism was fecal pollution of the contributing groundwater, which was unlikely due to the presence of latrines; instead, infiltration from contaminated surface water was more probable. The reduction in fecal sources in the environment in Juba is thus recommended, for example, through constructing latrines or designating protection areas near water sources. The study results contribute to the understanding of microbiological contamination of groundwater sources in areas with low incomes and high population densities, tropical climates and weathered basement complex environments, which are common in urban sub-Saharan Africa.

Research areas: Water Quality, Public Health
Population-dependent acclimatization capacity of thermal tolerance in larvae of the rocky-shore barnacle Pollicipes elegans (2015)

As environmental temperatures increase and become more seasonally variable, the ability of individuals to plastically alter their physiological responses to temperature (=acclimatize) may affect the potential for species persistence. Among marine organisms, the larval stage is often the most physiologically sensitive; larvae are also often the main dispersal stage in the life history. However, studies that address the acclimatization of marine larvae are rare. We investigated whether larvae of the gooseneck barnacle Pollicipes elegans from two temperate populations, one from the Northern Hemisphere (Mexico) and one from the Southern Hemisphere (Peru), show patterns of seasonal acclimatization to temperature. We compared the effects of temperature on swimming activity, oxygen consumption, and mortality of larvae from the two populations in both warm and cold seasons. Larvae from Mexico had higher thermal tolerances when collected in the boreal summer compared to the boreal winter, while no similar indication of seasonal acclimatization was seen in larvae from Peru. The lack of acclimatization in larvae of P. elegans from Peru may be related to recent thermal history, low selection for acclimatization due to irregular patterns of seasonal temperature change during ENSO events, or to different phylogeographic histories of Northern- and Southern-hemisphere populations.

Research areas: Ecosystems
PM10 and PM2.5 composition over the Central Black Sea: origin and seasonal variability (2015)

Daily PM10 and PM2.5 samples were collected between April 2009 and July 2010 at a rural site (Sinop) situated on the coast of the Central Black Sea. The concentrations of PM10 and PM2.5 were 23.2  16.7 and 9.8  6.9 g m3, respectively. Coarse and fine filters were analyzed for Cl, NO3, SO42, C2O42, PO43, Na+, NH4+, K+, Mg2+, and Ca2+ by using ion chromatography. Elemental and organic carbon content in bulk quartz filters were also analyzed. The highest PM2.5 contribution to PM10 was found in summer with a value of 0.54 due to enhanced secondary aerosols in relation to photochemistry. Cl, Na+, and Mg2+ illustrated their higher concentrations and variability during winter. Chlorine depletion was chiefly attributed to nitrate. Higher nssCa2+ concentrations were ascribed to episodic mineral dust intrusions from North Africa into the region. Crustal material (31 %) and sea salt (13 %) were found to be accounted for the majority of the PM10. The ionic mass (IM), particulate organic matter (POM), and elemental carbon (EC) explained 13, 20, and 3 % of the PM10 mass, correspondingly. The IM, POM, and EC dominated the PM2.5 (~74 %) mass. Regarding EU legislation, the exceeded PM2.5 values were found to be associated with secondary aerosols, with a particular dominance of POM. For the exceeded PM10 values, six of the events were dominated by dust while two and four of these exceedances were caused by sea salt and mix events, respectively.

Research areas: Water Quality
Physical and Anthropogenic Factors (2015)

Natural hazards are controlled by many physical and anthropogenic factors that govern the level of risk and its geographic distribution. These factors vary between regions and are not well defined; different studies have produced contradictory findings. The present study investigated the fundamental factors that influence floods and torrents in Jeddah city and the surrounding area, based on the flood events that took place in 2009 and 2011.

Research areas: Floods
Patterns of energy exchange for tropical ecosystems across a climate gradient in Mato Grosso, Brazil (2015)

The spatial and temporal variations in the partitioning of energy into latent (LE) and sensible (H) heat flux for tropical ecosystems are not yet fully understood. In the state of Mato Grosso State, Brazil, there are three different ecosystems (Cerrado, Pantanal and the Amazon Rainforest) with distributions that vary across rainfall and humidity gradients. Our goal was to analyze the seasonal variation in microclimate, spectral reflectance, LE and H for these ecosystems and quantify how energy partitioning varies across the regional climate gradient. We used the Bowen ratio energy balance method to estimate the LE and H of a dense, evergreen ombrophylous forest near Alta Floresta (AFL), a semi-deciduous forest in the Amazon-Cerrado transition zone near Sinop (SIN), a savanna grassland at Fazenda Miranda (FMI), a managed savanna pasture at Fazenda Experimental (FEX), a seasonally flooded woodland at Baia das Pedras in the Pantanal (BPE), and a riparian forest dominated by Vochysia divergens Pohl (CAM) in the Pantanal. Annual rainfall decreased from north to south, and 83% of the annual rainfall occurred during the wet season. However, the seasonal amplitude of volumetric soil water content (VSWC) increased from north to south, because of the increased potential for seasonal flooding. The vapor pressure deficit (VPD), air temperature, solar radiation (Rg) and net radiation (Rn) also increased from north to south, which directly affected the seasonal amplitude in the enhanced vegetation index (EVI). Our data suggest that energy partitioning in the wettest sites (AFL and CAM) were driven by solar radiation instead of soil water availability, while seasonal variation in rainfall was more important for the Amazon-Cerrado transitional forest (SIN), Cerrado (FMI and FEX) and Pantanal scrublands (BPE). These patterns are discernable using appropriate satellite vegetation indices, such as the EVI, allowing spatial and temporal variations in energy partitioning to be quantified across diverse landscapes like the Amazon Basin.

Research areas: Ecosystems
Particle sources and downward fluxes in the eastern Fram strait under the influence of the west Spitsbergen current (2015)

The carbon cycle of the Arctic Ocean is tightly regulated by landatmospherecryosphereocean interactions. Characterizing these environmental exchanges and feedbacks is critical to facilitate projections of the carbon cycle under changing climate conditions. The environmental drivers of sinking particles including organic carbon (OC) to the deep-sea floor are investigated with four moorings including sediment traps and currentmeters at the Arctic gateway in the eastern Fram Strait, which is the area where warm anomalies are transported northwards to the Arctic. Particles fluxes were collected over one year (July 2010July 2011) and have been analysed to obtain the content of the lithogenic fraction, calcium carbonate, OC and its stable isotopes, opal, and the grain size. Records of near bottom current speed and temperature along with satellite observations of sea ice extent and chlorophyll-a concentration have been used for evaluation of the environmental conditions. We found increased lithogenic fluxes (up to 9872mgm2d1) and coarsening grain size of settling particles in late winterearly spring. At the same time, intensifications of the northward flowing west Spitsbergen current (WSC) were recorded. The WSC was able to resuspend and transport northwards sediments that were deposited at the outlet of Storfjordrenna and on the upper slope west of Spitsbergen. The signal of recurrent winnowing of fine particles was also detected in the top layer of surface sediments. In addition, an increased arrival of sea ice transported ice rafted detritus (>414 detrital carbonate mineral grains larger than 1mm per m2) from the southern Spitsbergen coast along with terrestrial organic matter was observed beyond 1000m of water depth during winter months. Finally, the downward particle fluxes showed typical temporal variability of high latitudes, with high percentages of the biogenic compounds (opal, organic carbon and calcium carbonate) linked to the phytoplankton bloom in springsummer. However, on an annual basis local planktonic production was a secondary source for the downward OC, since most of the OC was advected laterally by the WSC. Overall, these observations demonstrated the sensitivity of the downward flux of particles to environmental conditions such as hydrodynamics, sea ice rafting, and pelagic primary production. Future alteration of the patterns of natural drivers due to climate change is thus expected to cause major shifts in the downward flux of particles, including carbon, to the deep sea ecosystems.

Research areas: Ecosystems
Ozone and aerosol tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF and CHIMERE models (2015)

Abstract. During the months of June and July 2013, over the EuroMediterranean area, the ADRIMED (Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) project was dedicated to characterize the ozone and aerosol concentrations in the troposphere. It is first shown that this period was not highly polluted compared to previous summers in this region, with a moderate ozone production, no significant vegetation fire events and several precipitation periods scavenging the aerosol. The period is modeled with the WRF (Weather Research and Forecasting) and CHIMERE models, and their ability to quantify the observed pollution transport events is presented. The CHIMERE model simulating all kinds of sources (anthropogenic, biogenic, mineral dust, vegetation fires); the aerosol speciation, not available with the measurements, is presented: during the whole period, the aerosol was mainly constituted by mineral dust, sea salt and sulfates close to the surface and mainly by mineral dust in the troposphere. Compared to the AERONET (Aerosol Robotic Network) size distribution, it is shown that the model underestimates the coarse mode near mineral dust sources and overestimates the fine mode in the Mediterranean area, highlighting the need to improve the model representation of the aerosol size distribution both during emissions, long-range transport and deposition.

Research areas: Validation
Oceanographic scenario and fish larval distribution off Guinea-Bissau (north-west Africa) (2015)

This paper describes the hydrography and the larval fish assemblage of Guinea Bissau waters, and analyses the spatial distribution of the main families in relation to the oceanographic features of the area. Data were obtained during an oceanographic survey, undertaken between October and November 2008. In addition to 98 demersal fishing hauls, a total of 33 stations, located between 20 and 1000 m depth, were sampled for hydrography and ichthyoplankton. Data showed that Guinea-Bissauan surface waters are characterized by a strong thermohaline front that flows parallel to the bathymetry of the area. Warm surface waters (SST > 29C) occupy the inner shelf, and colder (SST 

Research areas: Ecosystems
Observation and modeling of black soil wind-blown erosion from cropland in Northeastern China (2015)

As the nations bread basket, Northeastern China has experienced dramatic land use changes in the past decades, with much natural land being converted into cropland to feed the growing population. The long dormant season, coupled with frequent cold fronts and strong spring winds, makes the exposed cropland vulnerable to wind erosion. However, the rates and spatialtemporal characteristics of wind erosion in this particular soil type have been poorly studied. The present study aimed to measure and simulated the wind erosion characteristics from black soil cropland in the Dehui region of Northeastern China. Our results showed that wind-blown erosion was positively correlated with wind speed and negatively linked to soil moisture, vegetation and soil roughness in this region. The measured threshold friction velocity was 4.47m/s at 2m height, corresponding to 0.37m/s at the surface ground. Based on WRF-CMAQ-FENGSHA model, we localized the parameters and simulated a significant wind erosion event in the Dehui region on May 31, 2013. The relationships between modeled dust flux and ground measurement were correlated (R2=0.78). In addition, the modeled aerosol optical depths were also captured by satellite observations (MODIS and CALIPSO). Our results indicate that the bare farmland areas over Northeastern China are important dust sources over this region, and should not be neglected in regional air quality models. The use of protective farming techniques, protection of grassland and plowing in autumn for cropland areas should be considered to combat dust emission.

Research areas: Land Surface/Agriculture Indicators, Habitat Conversion/Fragmentation
Newly desertified regions in Iraq and its surrounding areas: Significant novel sources of global dust particles (2015)

Using the newly developed Middle East Dust Index (MEDI) applied to MODIS satellite data, we consider a relationship between the recent desertified regions, over the past three decades, and the dust source points identified during the period of 20012012. Results indicate that major source points are located in Iraq and Syria, and by implementing the spectral mixture analysis on the Landsat TM images (1984 and 2012), a novel desertification map was extracted. Results of this study indicate for the first time that c.a., 39% of all detected source points are located in this newly anthropogenically desertified area. Using extracted indices for Deep Blue algorithm, dust sources were classified into three levels of intensity: low, medium, and high. A large number of low frequency sources are located within or close to the newly desertified areas. These severely desertified regions require immediate concern at a global scale.

Research areas: Habitat Conversion/Fragmentation
Net Surface Shortwave Radiation from GOES ImageryProduct Evaluation Using Ground-Based Measurements from SURFRAD (2015)

The Earths surface net radiation controls the energy and water exchanges between the Earths surface and the atmosphere, and can be derived from satellite observations. The ability to monitor the net surface radiation over large areas at high spatial and temporal resolution is essential for many applications, such as weather forecasting, short-term climate prediction or water resources management. The objective of this paper is to derive the net surface radiation in the shortwave domain at high temporal (half-hourly) and spatial resolution (~1 km) using visible imagery from Geostationary Operational Environmental Satellite (GOES). The retrieval algorithm represents an adaptation to GOES data of a standard algorithm initially developed for the NASA-operated Clouds and Earths Radiant Energy System (CERES) scanner. The methodology relies on: (1) the estimation of top of atmosphere shortwave radiation from GOES spectral measurements; and (2) the calculation of net surface shortwave (SW) radiation accounting for atmospheric effects. Comparison of GOES-retrieved net surface shortwave radiation with ground-measurements at the National Oceanic and Atmospheric Administrations (NOAA) Surface Radiation (SURFRAD) stations yields very good agreement with average bias lower than 5 Wm2 and root mean square difference around 70 Wm2. The algorithm performance is usually higher over areas characterized by low spatial variability in term of land cover type and surface biophysical properties. The technique does not involve retrieval and assessment of cloud properties and can be easily adapted to other meteorological satellites around the globe.

Research areas: Validation
Natural disasters and land-use/land-cover change in the southwest coastal areas of Bangladesh (2015)

Natural hazards and major land-use/land-cover change can have significant impacts on humans around the world. If these two concerns exist together in a coastal area, the consequences for people and the environment may be severe. This study investigated the combined effects of land-use changes and natural disasters in the southwest coastal area of Bangladesh. Satellite images were analyzed to detect changes in land cover in the study period of 13 years (19992012). Three areas were selected for ground data collection. Household surveys and focus groups were conducted to discover the type, level and effects of disasters. Probit regression analysis was performed to assess the relationship between various disasters with overall income, agricultural production and outward migration. Results from image analysis showed an overall 30 % increase in shrimp culture ponds in the past 13 years. Agricultural land and vegetation decreased by 48 and 3 %, respectively. Barren and built-up areas increased by 73 % due to both land-use activity and natural hazards. Analysis of household data showed cyclones and storm surges had important effects on income, agricultural production and migration. Sustainable management and enhancement of resilience capacity of this area will be crucial in the near future.

Research areas: Land Surface/Agriculture Indicators, Habitat Conversion/Fragmentation, Severe Storms
Moisture sources and synoptic to seasonal variability of North Atlantic water vapor isotopic composition (2015)

AbstractThe isotopic composition of near surface (or planetary boundary layer) water vapor on the south coast of Iceland (63.83N, 21.47W) has been monitored in situ between November 2011 and April 2013. The calibrated data set documents seasonal variations in the relationship between 18O and local humidity (ppmv) and between deuterium excess and 18O. These seasonal variations are attributed to seasonal changes in atmospheric transport. A strong linear relationship is observed between deuterium excess and atmospheric relative humidity calculated at regional sea surface temperature. Surprisingly, we find a similar relationship between deuterium excess and relative humidity as observed in the Bermuda Islands. During days with low amount of isotopic depletion (more enriched values), our data significantly deviate from the global meteoric water line. This feature can be explained by a supply of an evaporative flux into the planetary boundary layer above the ocean, which we show using a 1-d box model. Based on the close relationship identified between moisture origin and deuterium excess, we combine deuterium excess measurements performed in Iceland and south Greenland with moisture source diagnostics based on back trajectory calculations to establish the distribution of d-excess moisture uptake values across the North Atlantic. We map high deuterium excess in the Arctic and low deuterium excess for vapor in the subtropics and midlatitudes. This confirms the role of North Atlantic water vapor isotopes as moisture origin tracers.

Research areas: Validation