nasa-gesdisc/es-publications-researchareas huggingface dataset:
Atmospheric and ionospheric precursors associated with Mw  6.5 earthquakes from multiple satellites (2022)

The ionospheric monitoring satellites aid in correlating the lithospheric variation in ionosphere through Lithosphere-Atmosphere-Ionosphere coupling (LAIC) over the epicenter of future earthquake (EQ). In the present paper, we studied variations in ionosphere associated to two large magnitude EQs (Mw  6.5) and low epicentral depth EQs of less than 12 km in Plasma Density (PD), Slant Total Electron Content (STEC) and Electron Temperature (ET) of European Space Agency's (ESA) Swarm-three satellites (Swarm-A, -B, and C). These anomalies are investigated in the Swarm data for 60 days before/after each main shock. The anomalies are detected by statistically implemented median (M) and standard deviation () method within the Dobrovolsky's area. In order to exclude the geomagnetic perturbations, we have selected the ionospheric data in quiet geomagnetic conditions. Anomalous variations in Swarm-A data occur in ET and STEC for the USA event, and similarly, significant perturbation is clear in STEC of Swarm-B before the Mw 6.5, USA. In case of Swarm-C, no clear anomalies associated with the USA event. Furthermore, Swarm-A, -B and C have abnormal post-seismic PD, STEC and ET responses to the Mw 6.7 Turkey EQ in the form intensive perturbations beyond the upper bound. We also study the atmospheric data over the epicenters in the form of Outgoing Longwave Radiation (OLR), Relative Humidity (RH), Surface Temperature (ST), and Air Temperature (AT) to support the Swarm observations. RH and ST show pre-seismic atmospheric anomalies before the USA EQ in the same anomalous time period as Swarm satellites. While, OLR, ST and AT have post-seismic atmospheric anomalies after the Turkey EQ within 1520-day period. The precursors chain from the lithosphere to the atmosphere, followed by the ionosphere are highlighted at different altitudes. The variations window for Swarm satellites and atmospheric indices are 5 days prior to USA main shock and one month after the Turkish EQ. Moreover, this study also aims to study the caliber of Swarm satellites for indicating seismo-ionospheric irregularities, which need more studies to delineate the LAIC hypothesis for future EQ.

Research areas: Earthquakes
Frequent Ultrafine Particle Formation and Growth in the Canadian Arctic Marine Environment (2017)

Abstract. The source strength and capability of aerosol particles in the Arctic to act as cloud condensation nuclei have important implications for understanding the indirect aerosol-cloud effect within the polar climate system. It has been shown in several Arctic regions that ultrafine particle (UFP) formation and growth is a key contributor to aerosol number concentrations during the summer. This study uses aerosol number size distribution measurements from ship-board measurement expeditions aboard the research icebreaker CCGS Amundsen in the summers of 2014 and 2016 throughout the Canadian Arctic to gain a deeper understanding of the drivers of UFP formation and growth within this marine boundary layer. UFP number concentrations (diameter > 4 nm) in the range of 101104 cm3 were observed across the two seasons, with concentrations greater than 103 cm3 occurring more frequently in 2016. Higher concentrations in 2016 were associated with UFP formation and growth, with events occurring on 41 % of days, while events were only observed on 6 % of days in 2014. Assessment of relevant parameters for aerosol nucleation showed that the median condensation sink in this region was approximately 1.2 h1 in 2016 and 2.2 h1 in 2014, which lie at the lower end of ranges observed at even the most remote stations reported in the literature. Apparent growth rates of all observed events in both expeditions averaged 4.3  4.1 nm h1, in general agreement with other recent studies at similar latitudes. Higher solar radiation, lower cloud fractions, and lower sea ice concentrations combined with differences in the developmental stage and activity of marine microbial communities within the Canadian Arctic were documented and help explain differences between the aerosol measurements made during the 2014 and 2016 expeditions. These findings help to motivate further studies of biosphere-atmosphere interactions within the Arctic marine environment to explain the production of UFP and their growth to sizes relevant for cloud droplet activation.

Research areas: Atmospheric/Ocean Indicators
Studies of forest fire induced changes in atmosphere over Uttarakhand, India, using space based observations and model simulations (2018)

The northern Indian state of Uttarakhand had witnessed an episode of intense forest fire during April-May 2016. The present study analyses the changes in trace gas and other atmospheric constituents induced by the forest fire using satellite data. The study reveals elevated levels of CO, NO2, ozone and aerosol optical depth (AOD) over the affected region. Higher levels of CO are observed at altitudes of 2-3 km. The column amount of CO has almost doubled from mean background values, whereas NO2 has increased by almost three times to values normally seen over highly polluted cities. Increase in ozone is only moderate and AOD has risen towards the end of the main phase of the fire episode. Weather research and forecasting simulations of wind and planetary boundary layer height are also performed and the results discussed. The study shows the potential of Earth-Observation Satellites to track and monitor such environmental impacts effectively.

Research areas: Wildfires, Air Quality
Assessment of the coronavirus disease 2019 (COVID-19) pandemic imposed lockdown and unlock effects on black carbon aerosol, its source apportionment, and aerosol radiative forcing over an urban city in India (2021)

A nationwide lockdown was imposed in India due to the Coronavirus Disease 2019 (COVID-19) pandemic which significantly reduced the anthropogenic emissions. We examined the characteristics of equivalent black carbon (eBC) mass concentration and its source apportionment using a multiwavelength aethalometer over an urban site (Ahmedabad) in India during the pandemic induced lockdown period of year 2020. For the first time, we estimate the changes in BC, its contribution from fossil (eBCff) and wood (eBCwf) fuels during lockdown (LD) and unlock (UL) periods in 2020 with respect to 2017 to 2019 (normal period). The eBC mass concentration continuously decreased throughout lockdown periods (LD1 to LD4) due to enforced and stringent restrictions which substantially reduced the anthropogenic emissions. The eBC mass concentration increased gradually during unlock phases (UL1 to UL7) due to the phase wise relaxations after lockdown. During lockdown period eBC mass concentration decreased by 35%, whereas during the unlock period eBC decreased by 30% as compared to normal period. The eBCwf concentrations were higher by 40% during lockdown period than normal period due to significant increase in the biomass burning emissions from the several community kitchens which were operational in the city during the lockdown period. The average contributions of eBCff and eBCwf to total eBC mass concentrations were 70% and 30% respectively during lockdown (LD1 to LD4) period, whereas these values were 87% and 13% respectively during the normal period. The reductions in BC concentrations were commensurate with the reductions in emissions from transportation and industrial activities. The aerosol radiative forcing reduced significantly due to the reduction in anthropogenic emissions associated with COVID-19 pandemic induced lockdown leading to a cooling of the atmosphere. The findings in the present study on eBC obtained during the unprecedented COVID-19 induced lockdown can provide a comprehensive understanding of the BC sources and current emission control strategies, and thus can serve as baseline anthropogenic emissions scenario for future emission control strategies aimed to improve air quality and climate.

Research areas: Atmospheric/Ocean Indicators, Environmental Impacts
Nocturnal Rainfall East of the Antilles Islands (2021)

We analyze nocturnal rainfall caused by the interaction of trade winds and land breezes on the windward flank of the islands of Guadeloupe, Dominica, and Martinique of the eastern Caribbean Antilles. Climatology for the 20002019 period and a nocturnal rainfall case study 89 February 2018 are supplemented by modern 525 km hourly resolution satellite and reanalysis products and station measurements that describe the diurnal cycle around the islands. Mean trade winds of 7 m s1 decelerate upstream, U/x less than 105 s1, causing an increase in warm-cloud rainfall from 2 to 4 mm d1 between 03:30 and 06:30 local time (local time is UTC-4). The incoming airflow has a characteristic Froude number less than 1 and stagnates on the windward slopes of these volcanic islands. Nocturnal land breezes spread toward the east coast about one-third of the time.Additional work considers whether airsea interactions play a role. Low salinity and wave-induced turbulence to the east of the Antilles add buoyancy and moisture to the atmospheric boundary layer. Yet areas of low turbidity encircling the east Antilles suggest that nocturnal airflow creates a divergent cushion around Guadeloupe, Dominica, and Martinique. Thermal and orographic influences merge and rain falls over the eastern flank of the islands, contributing to the water resources.

Research areas: Validation
Assessment of air quality changes during COVID-19 partial lockdown in a Brazilian metropolis: from lockdown to economic opening of Rio de Janeiro, Brazil (2021)

During the COVID-19 pandemic, restrictive measures are taken by several cities around the world, as well as Rio de Janeiro, reducing routine activities in large urban centers and primary pollutant emissions. This study aims to assess air quality during this partial lockdown through O3, CO, and PM10 concentrations and meteorological data collected in five air quality monitoring stations spread over the whole city, considering the substantial changes in city routine. The period evaluated starts in March 2020, when the partial lockdown was decreed, and ends in September 2020, when economic opening ended. Compared with 2019 data, CO concentration reduced significantly, as expected since the main source of these pollutants is vehicular traffic. O3 concentration increased, most probably as a consequence of the reduction in primary pollutants. On the other hand, PM10 concentration did not vary significantly. From June to September, pollutant concentrations increased responding to the economic opening. Thereby, the partial lockdown contributed to improving air quality in Rio de Janeiro City, which means that changes in work format may be an alternative to reduce atmospheric pollution in big cities, since home office contributes to mobility reductions, and consequently to vehicular emissions.

Research areas: Air Quality
Insular gazelles of the circum-Arabian seas: origin, distribution, dwarfism and taxonomy (2021)

The taxonomy of gazelles (Bovidae: Antilopinae) has been debated at length. Many of the species and subspecies were historically discriminated mostly on subtle and individually variable phenotypic differences, often on the basis of few, sometimes controversial museum specimens or captive individuals of uncertain origin. The resulting taxonomic confusion is particularly evident for insular populations, which often show slight phenotypic variations. We systematically review and update the past and present distribution of insular gazelles in the circum-Arabian seas, using the literature and reliable websites. Moreover, in light of the available genetic information, we discuss the taxonomic status of four endemic taxa, two of dwarf size. One or more gazelle species are or were present on 45 islands. The archaeozoological and historical data support an anthropochorous origin of most of these populations as a meat source. Lately, food supplied gazelles have been introduced for cultural reasons on many islands of the Persian Gulf. The nine molecularly studied insular populations show low genetic differentiation from their mainland relatives, which suggests their recent origin. Considering the limited genetic differentiation from the geographically closest continental population, we reassign Nanger soemmerringii debeauxi to the nominotypical subspecies. We advocate phenotypic plasticity, triggered by scarce food resources, as the most likely cause of dwarfism in the gazelles of Dahlak and Farasan archipelagos of the Red Sea. We stress the need to avoid unnecessary taxonomic proliferation before deep integrative research has been carried out, and we highlight the importance of research on phenotypic plasticity in insular gazelles.

Research areas: Ecosystems
Tributary-junction alluvial fan response to an ENSO rainfall event in the El Huasco watershed, northern Chile (2020)

Tributary-junction alluvial fans situated at the intersection of confined valleys with <100 km2 tributary catchments are of special interest to evaluate the heterogeneous consequences of extreme rainfall events in arid zones. These fans record the episodic sedimentological behaviour of the hillslope response to rainstorm events within tributary catchments, together with the influence on the main fluvial systems. In this paper, we benefit from the March 2015 event (2326 March 2015), which produced 7546 mm of precipitation over four days in the southern portion of the Atacama Desert. This storm event triggered several debris flows in El Huasco River watershed tributaries and, therefore, tributary-junction alluvial fans received a total of 106 m3 of sediments across 49 activated catchments. We find that the characteristic storm signature across the catchments can be synthetised in a conceptual fan formation model based on field mapping of facies (F1 to F6) present in the fans. The characteristic signature is a record of initially high sediment-to-water flows restricted to the fan environments (mainly debris flows) followed by later, more dilute (mainly hyper-concentrated to fluvial) flows that incise the tributary-junction alluvial fan deposits and link tributary catchments with the main river. These later-stage flood event deposits, locally, are capable of ponding and compartmentalising the main river where the longitudinal connectivity of the tributary-junction catchment is effective. This situation improves tributary-junction fan slope and main-trunk-channel linkages. This approach provides a reference framework for understanding the distribution and routing of effective runoff from similar rainfall events that control the aggradation and incision of the fluvial system, which is of great value when studying past stratigraphic arrangements in these arid alleys.

Research areas: Land Surface/Agriculture Indicators, Atmospheric/Ocean Indicators
Input of Terrestrial Material into Coastal Patagonian Waters and Its Effects on Phytoplankton Communities from the Chubut River Estuary (Argentina) (2021)

Riverine and eolian-dust inputs to coastal waters are influenced by both rainfall and land-use (i.e., deforestation, agriculture, urbanization). Transport of sediments and nutrients from rivers to the oceans are well- documented worldwide, and it is of major management concern because coastal ecosystems provide a great variety of products and services to humankind. Episodic, but extreme rainfall or dust-storm events can generate abrupt pulsed riverine/eolian discharge events, thus increasing nutrients and sediments in surface waters. It is expected that they will be intensified in the upcoming decades by global change, but we scarcely know how they could impact on coastal planktonic communities. In this chapter we address the main terrestrial material transported via rivers and winds in Patagonian coastal waters of the South West Atlantic Ocean (SWAO) and their impact on the structure and functioning of phytoplankton communities. The rivers in Patagonia carry not only sewage from the cities that lie on their margins, but also heavy loads of nutrients, due to agricultural and cattle raising activities upstream from their mouths; extreme rainfall events increase these inputs manyfold. Eolic inputs are also important over Patagonia because this area has a strong prevalence of winds from the west, carrying a wide variety of particles that are blown far into the ocean, especially after volcanic eruptions. We used the Chubut river estuary (Patagonia) as a reference coastal ecosystem in the SWAO to assess how riverine and eolic inputs impact on phytoplankton which are the base of one of the most productive fisheries areas of the SWAO. Overall, nutrient inputs of terrestrial origin, improved phytoplankton growth, photosynthesis performance and changed the community structure towards a dominance of mostly nanoplanktonic diatom species . These responses, however, might vary due to the interaction of terrestrial material inputs with other global change drivers such as warming, acidification, vertical mixing or solar ultraviolet radiation.

Research areas: Ecosystems, Environmental Impacts
Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol (2015)

Abstract. The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather Research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region, by coupling a sectional aerosol scheme to the plume-rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign.  WRF-Chem predicted layers of elevated aerosol loadings (520 g sm3) of particulate organic matter at high altitude (68 km) over tropical forest regions, while flight measurements showed a sharp decrease above 24 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AODs). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 45 km altitude. Over eastern cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude.  Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.31.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern cerrado regions, WRF-Chem tended to under-predict AODs. Modelled aerosol loadings in the east were higher in the modified emission scenario. The primary organic matter to black carbon ratio was typically between 810 in WRF-Chem. This was lower than the western flight measurements (interquartile range of 11.615.7 in B734, 14.724.0 in B739), but similar to the eastern flight B742 (8.110.4). However, single scattering albedo was close to measured over the western flights (0.870.89 in model; 0.860.91 in flight B734, and 0.810.95 in flight B739 measurements) but too high over the eastern flight B742 (0.860.87 in model, 0.790.82 in measurements). This suggests that improvements are needed to both modelled aerosol composition and optical properties calculations in WRF-Chem.

Research areas: Environmental Impacts
Summer Heatwave Impacts on the European Kelp Saccharina latissima Across Its Latitudinal Distribution Gradient (2021)

Kelps are important foundation species in coastal ecosystems currently experiencing pronounced shifts in their distribution patterns caused by ocean warming. While some populations found at species warm distribution edges have been recently observed to decline, expansions of some species have been recorded at their cold distribution edges. Reduced population resilience can contribute to kelp habitat loss, hence, understanding intraspecific variations in physiological responses across a species latitudinal distribution is crucial for its conservation. To investigate potential local responses of the broadly distributed kelp Saccharina latissima to marine heatwaves in summer, we collected sporophytes from five locations in Europe (Spitsbergen, Bod, Bergen, Helgoland, Locmariaquer), including populations exposed to the coldest and warmest local temperature regimes. Meristematic tissue from sporophytes was subjected to increasing temperatures of +2, +4 and +6C above the respective mean summer temperatures (control, 0C) characteristic for each site. Survival and corresponding physiological and biochemical traits were analyzed. Vitality (optimum quantum yield, Fv/Fm) and growth were monitored over time and biochemical responses were measured at the end of the experiment. Growth was highest in northern and lowest in southern populations. Overall, northern populations from Spitsbergen, Bod and Bergen were largely unaffected by increasing summer temperatures up to +6C. Conversely, sporophytes from Helgoland and Locmariaquer were markedly stressed at +6C: occurrence of tissue necrosis, reduced Fv/Fm, and a significantly elevated de-epoxidation state of the xanthophyll cycle (DPS). The variations in phlorotannins, mannitol and tissue C and N contents were independent of temperature treatments and latitudinal distribution pattern. Pronounced site-specific variability in response to increasing temperatures implies that exceeding a threshold above the mean summer temperature exclusively affect rear-edge (southernmost) populations.

Research areas: Ecosystems, Atmospheric/Ocean Indicators
Landslides Triggered by the May 2017 Extreme Rainfall Event in the East Coast Northeast of Brazil (2021)

Given the increasing occurrence of landslides on the East Coast Northeast of Brazil (ECNEB), it is essential to understand its conditions and triggering factors because meteorological anomalies triggered by a landslide will threaten life and property in the region. In this sense, this research aimed to diagnose the meteorological conditions that triggered landslides in the ECNEB in May 2017, evaluate the terrains intrinsic conditions using elevation, slope, and susceptibility parameters and determine critical precipitation thresholds for the city with the highest number of landslide risk areas in the region. A dynamic downscaling experiment was carried out using the Regional Climate Model (RegCM) to verify the ability of this model to represent rainfall over the ECNEB. The results from the intrinsic factors showed that the ECNEB is highly susceptible to landslides with various high-risk sectors for landslides to the population. The extreme rainfall event was associated with the convergence of humidity at low levels over the ocean, which contributed to landslides in the ECNEB, mainly in the State of Pernambuco, where 67 landslides were registered. The RegCM numerical simulation underestimated the high daily rainfall signal seen on the Tropical Rainfall Measuring Mission satellite. It is suggested that sensitivity tests can be performed using other physical parameters to find the best model configuration for the ECNEB. This work recommends that exploring the relationship between precipitation and landslides will provide objective criteria for assessing risk areas by contributing to the predictability of disasters in this region.

Research areas: Land Surface/Agriculture Indicators, Atmospheric/Ocean Indicators