nasa-gesdisc/es-publications-researchareas huggingface dataset:
Remote Sensing of Atmospheric and Ionospheric Signals Prior to the Mw 8.3 Illapel Earthquake, Chile 2015 (2017)

In the present study, a number of atmospheric and some ionospheric anomalies are analyzed, which were recorded prior to the Mw 8.3 Illapel earthquake of September 16, 2015. This very large earthquake occurred in Central Chile, close to the coast, as the result of thrust faulting on the interface between the Nazca Plate and South American continent. Using remotely sensed data extracted from NASA/Giovanni, NOAA/NCEP, and NOAA/NGDC, atmospheric and ionospheric anomalies were observed that co-registered 3540 and 2530 days prior to the main shock, respectively. With reference to long-term time series over the epicentral area, significant atmospheric anomalies were recorded for cloud cover, geopotential height, precipitation rates, surface air pressure, omega, stream function, and wind vectorsall in the time window of August 510, 2015, 3540 days prior to the main shock. Anomalous TEC maps were recorded for the same time period. Satellite images indicate the formation of an unusual cyclone, presumably triggered by air turbulences and abnormal atmospheric conditions over the epicentral area, including strong vertical winds. Data from the Jicamarca radio observatory in Peru, more than 2000 km to the North, reveal anomalous ionospheric variations on August 1520, 2015 with respect to international reference ionosphere thickness parameters and the altitude of the F layer. The observed anomalies are consistent with processes that occur at the ground-to-air interface due to the stress activation of peroxy defects in the hypocentral volume. The flow of positive hole charge carriers to the Earth surface expected to have led to massive air ionization, generating at first primarily positive airborne ions, then negative air ions plus ozone. Understanding the sequence of processes inside the Earths crust and at the ground-to-air interface provides information not previously available about the causal and temporal linkages between the various pre-earthquake phenomena and the future seismic event.

Research areas: Earthquakes
The impact of COVID 19 on air pollution levels and other environmental indicators - A case study of Egypt (2021)

The outbreak of coronavirus disease (COVID-19) not only affected health and economics, but also its effect extended to include other aspects, such as the environment. Using Egypt as a case study, this paper presents the impact of COVID-19 pandemic on air pollution levels by studying nitrogen dioxide (NO2), ozone (O3), particulate matter represented in absorbing aerosol index (AAI), carbon monoxide (CO), and greenhouse gas (GHG) emissions. The paper also highlights the impact of COVID-19 pandemic on other environmental indicators including environmental noise, medical and municipal solid wastes. The paper presents the Egyptian COVID-19 story from its different angles including the development of confirmed COVID-19 cases, containment measures from the government, the impact on the country's economy and the national energy consumption so as to effectively evaluate the effect on both the air pollution levels and the other studied environmental indicators. For the other environmental indicators, a strong link was observed between COVID-19 lockdown and the reduction in environmental noise, beaches, surface and groundwater pollution. For environmental noise, this has been confirmed by officially governmental announcements which reported that the level of environmental noise in Egypt was reduced by about 75% during the lockdown period. On the other hand, there are some negative effects, including an increase in medical solid waste (from 70 to 300 ton/day), municipal solid waste, as well as a less efficient solid waste recycling process. For air pollution levels, the data were obtained from National Aeronautics and Space Administration (NASA) and European Space Agency satellite data sets. The data for the lockdown period in 2020 have been extracted and compared to the corresponding months in the selected baseline period (20152019) to identify the effect that the lockdown period had on the air pollution levels in Egypt with focus on Cairo and Alexandria governorates. It was found that the AAI decreased by about 30%, the NO2 decreased by 15 and 33% over Cairo and Alexandria governorates, respectively, and that the CO decreased by about 5% over both governorates. In addition, the GHG emissions in Egypt were reduced by at least 4% during the pandemic. In contrast, ozone levels increased by about 2% over Cairo and Alexandria governorates. It can be concluded that the implemented containment measures during COVID-19 pandemic had resulted in both positive and negative environmental impacts. The positive environmental impacts are not sustainable and deterioration on them is expected to occur after the lockdown as it was before the pandemic. Therefore, stricter laws must be enacted to protect the environment in Egypt.

Research areas: Air Quality, Greenhouse Gases
A Spatial Econometric Analysis of Air Pollutant Concentrations and Economic Growth on Public Health: Empirical Evidence from Central Asian Countries (2021)

Air pollution of the countries of Central Asia has affected not only the health of the population since 1990 but also influenced the environment. This study has been made empirically analyzes the spatial autocorrelation analysis that is based on the 1991 to 2017 database of Central Asian countries on the socio-economic factors influencing the concentration of Sulfur Dioxide (SO2), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Ozone (O3), and Particulate Matter (PM2.5) in the air. Besides, this study validated Global Moran's I statistics to determine spatial positive autocorrelations. The results show that there is a strong correlation between air pollution concentrations and Gross Domestic Product (GDP) per capita. The achievement identified that the concentrations of SO2, CO, NO2, O3, and PM2.5 have a spatial aggregation and distribution effect, which is significantly influenced by the spatial characteristics and the Central Asian Regional Economic Unions. It also determined that an energy policy of a country can be affected the emissions of air pollutants from neighboring countries due to policy effects. Therefore, there is a need for regional coordination of environmental policies and the transfer of pollution-intensive industries, to keep air pollution in countries of Central Asia at a normal level. In addition to the empirical results of this study, the following two conclusions can be identified. First, it identified the need for a unified policy to reduce air pollution to reduce emissions from air pollution sources. Second, there is a need for a renewable energy policy for the development and promotion of renewable energy.

Research areas: Air Quality
Study of Thermal Fields before Strong Earthquakes in Turkey on March 8, 2010 (M = 6.1), and January 24, 2020 (M = 6.7) (2021)

Thermal-field anomalies recorded during the preparation and occurrence of strong earthquakes on March 8, 2010 (M = 6.1), and January 24, 2020 (M = 6.7), in Turkey, are studied using satellite data. Temperatures of the surface and atmospheric near-surface layer, as well as outgoing longwave radiation registered by the AIRS sensor of the Aqua satellite, are used for the analysis. The processing results have allowed us to establish that positive variations in surface and atmosphere temperatures appeared 712 days before the studied seismic events with M = 6.1 and M = 6.7, and these variations marked the onset of formation of the outgoing longwave radiation anomalies registered over the North and East Anatolian tectonic faults. The thermal-field anomalies detected during the preparation of the earthquakes in Turkey confirm the presence of heat generation effects between the surface and the upper cloud edge. These effects can be used as short-term remotely registered precursors of strong seismic events.

Research areas: Earthquakes
Suitability of the Coralline Alga Clathromorphum compactum as an Arctic Archive for Past Sea Ice Cover (2022)

Arctic sea ice cover has been steeply declining since the onset of satellite observations in the late 1970s. However, the available annually resolved sea ice data before this time are limited. Here, we evaluated the suitability of annual trace element (Mg/Ca) ratios and growth increments from the long-lived annual increment-forming benthic coralline red alga, Clathromorphum compactum, as high-resolution sea ice cover archive. It has previously been shown that the growth of C. compactum is strongly light controlled and therefore greatly limited during the polar night and underneath sea ice cover. We compare algal data from 11 sites collected throughout the Canadian Arctic, Greenland, and Svalbard, with satellite sea ice data. Our results suggested that algal growth anomalies most often produced better correlations to sea ice concentration than Mg/Ca ratios or when averaging growth and Mg/Ca anomalies. High Arctic regions with persistently higher sea ice concentrations and shorter ice-free seasons showed the strongest correlations between algal growth anomalies and satellite sea ice concentration over the study period (19792015). At sites where ice breakup took place before the return of sufficient solar irradiance, algal growth was most strongly tied to a combination of solar irradiance and other factors such as temperature, suspended sediments, phytoplankton blooms, and cloud cover. These data are the only annually resolved in situ marine proxy data known to date and are of utmost importance to gain a better understanding of the sea ice system and to project future sea ice conditions.

Research areas: Cryospheric Indicators, Ecosystems
Solar Potential in Saudi Arabia for Flat-Plate Surfaces of Varying Tilt Tracking the Sun (2021)

The objective of the present work is to investigate the performance of flat-plate solar panels in Saudi Arabia that continuously follow the daily motion of the sun. To that end, the annual energy sums are estimated for such surfaces at 82 locations covering all Saudi Arabia. All calculations use a surface albedo of 0.2 and another one with a near-real value. The variation of the solar energy sums on annual, seasonal, and monthly basis is given for near-real ground albedos; the analysis provides regression equations for the energy sums as function of time. A map of the annual inclined solar energy for Saudi Arabia is derived and presented. The annual energy sums are found to vary between 2159 and 4078 kWhm2year1. Finally, a correction factor, introduced in a recent publication, is used; it is confirmed that the linear relationship between the correction factor and the ground-albedo ratio is general enough to be graphically representable as a nomogram. A discussion regarding the differences among solar systems on horizontal, fixed-tilt, 1-axis, and 2-axis systems is presented.

Research areas: Energy Production/Use, Sun-Earth Interactions
Quantifying the impact of biomass burning and dust storm activities on aerosol characteristics over the Indo-Gangetic Basin (2022)

The high aerosol loading over the entire Indo-Gangetic Basin (IGB) region in the northern India attracted attentions of scientific community especially when about 900 million people living in the areas suffered with poor air quality due to intense fog, haze and smog during the post-monsoon/winter period and dust storm activity during the summer period. The present study focused on first long-term comparative study to quantify the aerosol characteristics during the biomass burning (October-November) and dusty (April-June) periods using satellite measurements from 2004-2018 at three different locations: Jaipur, Kanpur and Ballia over IGB. The highest aerosol optical depth (AOD) values for the biomass (0.74  0.35) and dusty period (0.63  0.34) were observed at Kanpur during the entire study period. The finer particles were found to be dominant during the biomass period at all the locations. During the biomass burning period, an increased AOD trend was observed at Ballia (0.017 year1), followed by Kanpur (0.0144 year1) and Jaipur (0.0061 year1) whereas during the dusty period, an increasing trend was observed at Ballia (0.0074 year1) and decreasing trend over Jaipur (0.0132 year1) and Kanpur (0.0083 year1). During the biomass burning period, anthropogenic aerosol (AA) types were found to be dominant over Kanpur (52%) and Ballia (56%) while clean condition (CC) aerosol type was dominant over Jaipur (69%). On the other hand, during dusty period, the highest contribution of desert dust (DD) was observed at Kanpur (37%) and Ballia (30%); however, CC type of aerosol dominated over Jaipur (42%). The potential source sectors and the transport pathways of pollutants have been widely characterized at all the stations using the potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analyses with the backward air mass trajectories. Results revealed that the high levels of aerosol over the stations are mainly from the local areas and also from the upper and middle IGB region.

Research areas: Environmental Impacts, Air Quality
Could road constructions be more hazardous than an earthquake in terms of mass movement? (2022)

Roads can have a significant impact on the frequency of mass wasting events in mountainous areas. However, characterizing the extent and pervasiveness of mass movements over time has rarely been documented due to limitations in available data sources to consistently map such events. We monitored the evolution of a road network and assessed its effect on mass movements for a 11-year window in Arhavi, Turkey. The main road construction projects run in the area are associated with a hydroelectric power plant as well as other road extension works and are clearly associated with the vast majority (90.1%) of mass movements in the area. We also notice that the overall number and size of the mass movements are much larger than in the naturally occurring comparison area. This means that the sediment load originating from the anthropogenically induced mass movements is larger than its counterpart associated with naturally occurring landslides. Notably, this extra sediment load could cause river channel aggregation, reduce accommodation space and as a consequence, it could lead to an increase in the probability and severity of flooding along the river channel. This marks a strong and negative effect of human activities on the natural course of earth surface processes. We also compare frequency-area distributions of human-induced mass movements mapped in this study and co-seismic landslide inventories from the literature. By doing so, we aim to better understand the consequences of human effects on mass movements in a comparative manner. Our findings show that the damage generated by the road construction in terms of sediment loads to river channels is compatible with the possible effect of a theoretical earthquake with a magnitude greater than Mw = 6.0.

Research areas: Habitat Conversion/Fragmentation, Land Surface/Agriculture Indicators, Earthquakes
Evaluation of Biogenic Organic Aerosols in the Amazon Rainforest Using WRF-Chem With MOSAIC (2021)

Biogenic secondary organic aerosol (BSOA) accounts for 70%80% of submicron aerosol over the Amazon rainforest. However, uncertainties with regard to the chemical formation pathway, mass budget, and radiative impact of BSOA in the region still remain high. To address the issue, we used a regional chemistry transport model (WRF-Chem-MOSAIC) to evaluate the budget of BSOA in the Amazon forest during the wet season (March) of 2014 when the air mass was clean from influences from anthropogenic and biomass burning emissions. We found that the default model underestimated the surface concentration of submicron organic aerosol (OA) by 57% at a ground measurement site (T3). We subsequently updated the WRF-Chem-MOSAIC model by including SOA formation from isoprene epoxydiols (IEPOX-SOA) and SOA aging schemes. The updated model reproduced the observed submicron OA concentration well with an overestimation of only 2.5%. With the updated model, we will show that IEPOX-SOA accounts for 23% of surface submicron OA averaged over the entire Amazon rainforest. The modeled surface SOA (smaller than 2.5 m in diameter) concentration in the Amazon region was about a factor of 14 larger than the global mean. Finally, a sensitivity study was conducted which showed that convective plumes can remove more than 40% of submicron OA below 5 km in the Amazon region. Overall, our study highlights the importance of IEPOX chemistry as well as the convective removal processes in the global SOA budget.

Research areas: Environmental Impacts
Exploring Possible Influence of Dust Episodes on Surface Marine Chlorophyll Concentrations (2019)

Desert dust deposition is thought to act as fertilizer for phytoplankton growth, since it is
rich in the required nutrients. The Mediterranean Sea is a nutrient poor marine environmentwith
its eastern part being the most oligotrophicwhich is subject to dust transport. The Hellenic
Seas are part of this low-nutrient, low-chlorophyll environment and they are also affected by dust
deposition events. Thus, the dust fertilizing effect can be particularly important, especially during
the stratification period, when the nutrients needed for phytoplankton growth are not imported from
deeper layers. Some individual dust events are examined here in respect of their possible influence on
phytoplankton, through the observed variations of satellite derived chlorophyll concentrations. Two
strong dust events that were also extreme weather events and three events in the JuneSeptember
stratification period are examined for the Hellenic Seas as well as a strong dust event in the Central
Mediterranean Sea. The results, only when based on absolute chlorophyll differences above 50%, show
that dust events seem to favour phytoplankton abundance mainly during the low productive period;
however, these differences are area-limited. The difficulty of reaching safe results through specific dust
events and discriminating between other meteorological factors favouring phytoplankton growth are
also discussed.

Research areas: Ecosystems
Spatiotemporal monitoring of CO2 and CH4 over Pakistan using Atmospheric Infrared Sounder (AIRS) (2016)

Carbon dioxide (CO 2 ), Methane (CH 4 ) are two most potent greenhouse gases and are
major source of climate change. Human activities particularly fossil fuels burning have caused
considerable increase in atmospheric concentrations of greenhouse gases. CO 2 contributes 60% of
anthropogenic greenhouse effect whereas CH 4 contributes 15%. Ice core records also show that the
concentrations of Carbon dioxide and methane have increased substantially. The emission of these
gases alters the Earths energy budget and are drivers of climate change. In the present study,
atmospheric concentration of CO 2 and CH 4 over Pakistan is measured using Atmospheric Infrared
Sounder (AIRS). Time series and time averaged maps are prepared to measure the concentrations of
CO 2 and CH 4 . The results show considerable increase in concentration of Carbon dioxide and
methane. The substantial increase in these concentrations can affect human health, earth radiative
balance and can damage crops.

Research areas: Greenhouse Gases
Can Forest Fires Be an Important Factor in the Reduction in Solar Power Production in India? (2022)

The wildfires over the central Indian Himalayan region have attracted the significant attention of environmental scientists. Despite their major and disastrous effects on the environment and air quality, studies on the forest fires impacts from a renewable energy point of view are lacking for this region. Therefore, for the first time, we examine the impact of massive forest fires on the reduction in solar energy production over the Indian subcontinent via remote sensing techniques. For this purpose, we used data from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO), the Satellite Application Facility on support to Nowcasting/Very Short-Range Forecasting Meteosat Second Generation (SAFNWC/MSG) in conjunction with radiative transfer model (RTM) simulation, in addition to 1-day aerosol forecasts from the Copernicus Atmosphere Monitoring Service (CAMS). The energy production during the first quarter of 2021 was found to reach 650 kWh/m2 and the revenue generated was about INR (Indian rupee) 79.5 million. During the study period, the total attenuation due to aerosols and clouds was estimated to be 116 and 63 kWh/m2 for global and beam horizontal irradiance (GHI and BHI), respectively. The financial loss due to the presence of aerosols was found to be INR 8 million, with the corresponding loss due to clouds reaching INR 14 million for the total Indian solar plants capacity potential (40 GW). This analysis of daily energy and financial losses can help the grid operators in planning and scheduling power generation and supply during the period of fires. The findings of the present study will drastically increase the awareness among the decision makers in India about the indirect effects of forest fires on renewable energy production, and help promote the reduction in carbon emissions and greenhouse gases in the air, along with the increase in mitigation processes and policies.

Research areas: Wildfires, Energy Production/Use, Sun-Earth Interactions
Evaluation of surface solar radiation trends over China since the 1960s in the CMIP6 models and potential impact of aerosol emissions (2022)

Accurate representation of surface solar radiation (SSR) trends is an important indicator for global climate models (GCMs) to correctly reproducing the historical climate evolution. This study examines the annual mean SSR trends in China under all-sky and clear-sky conditions for the period 19612014 in 34 Coupled Model Intercomparison Project Phase 6 (CMIP6) models using the latest homogenized in-situ SSR dataset. The site-observed annual mean SSR over China shows a significant decadal decline during 19612005 but an uptrend during 20062014, with the trends being 6.4 (8.6) W m2 and + 2.5 (+5.9) W m2 per decade under all-sky (clear-sky) condition, respectively. All CMIP6 models simulate the sustained decline in SSR over China for the period 19612005 but significantly underestimate the dimming. The model results show trends of 1.9  0.5 W m2 and -2.5  0.7 W m2 per decade during 19612005 under all-sky and clear-sky conditions, respectively, which are around one third of the observed results. Furthermore, the models fail to capture the reversal of SSR trends in China during 20062014, with the trends being 1.1  1.7 W m2 and -2.2  0.9 W m2 per decade under all-sky and clear-sky conditions, respectively. We infer that the underestimation of anthropogenic aerosol emissions, especially absorbing black carbon emissions cause the underestimated simulation of SSR in dimming period over China. After 2005, the unseasonal increase in carbonaceous aerosol emissions and the weaker decline of sulfur dioxide emissions in China in the models result in an opposite SSR trends relative to the trends based on the site-observations. Our results suggest that improving the anthropogenic aerosol emissions inventory will be useful for generating a more accurate reproduction of the regional SSR evolution over China in GCMs.

Research areas: Sun-Earth Interactions