nasa-gesdisc/es-publications-researchareas huggingface dataset:
Understanding the relationship among factors influencing rural tourism: a hierarchical approach (2021)

Purpose The aim of this paper is to analyze the interrelationship between factors conducive to rural tourism development. This touristic segment has enormous potential but still lacks consistent means and measures to ensure rural tourism's holistic development in India. Design/methodology/approach The study identified 14 factors, of which nine are from the literature review and five are from interaction with the experts, which influence rural tourism development. The research design comprises three segments, i.e. identifying factors from the literature and expert opinion, conducting interviews with the academic experts and managers, and analyzing the responses recorded. Interpretive structural modeling (ISM) technique is used to determine the interlinkage between the factors and develop a hierarchical relationship. Findings The results indicate that infrastructure development, growing environmental conscience, support of local government and community, availability of funds with the government and participation of the private sector are the primary factors channelizing rural tourism development. Also, attitudes of locals to adapt, tourist travel motives, marketing of the destination, destination characteristics and recommendation by others are the major dependent factors identified. The findings broaden the knowledge on suitable channels for rural tourism development and provide vital information for the formulation of flexible strategies for developing rural tourism in India. Originality/value This paper's originality lies in providing information to clarify the relationships between factors conducive to rural tourism development, an area where limited research has been done.

Research areas: Habitat Conversion/Fragmentation
Assessing the Causes of Tropical Forest Degradation Using Landsat Time Series: A Case Study in the Brazilian Amazon (2021)

Monitoring forest degradation at fine scale over large area is critical from an environmental point of view since it provides crucial information for many ecological applications. We introduce an automatic method based on optical Landsat time series (20002017) to detect and quantify forest disturbances and to identify the causes of forest degradation. The method is based on i) an automatic spectral unmixing to detect forest's disturbances and on ii) landscape metrics and temporal indicators to detect the causes of forest degradation. We applied the approach in the Brazilian Amazon municipality of Paragominas to map forested areas affected by reduced impact logging, conventional logging or illegal logging and fires.

Research areas: Habitat Conversion/Fragmentation
Estimation of component contributions to total terrestrial water storage change in the Yangtze river basin (2021)

Terrestrial water storage (TWS) is a key variable in global and regional hydrological cycles. In this study, the TWS changes in the Yangtze River Basin (YRB) were derived using the Lagrange multiplier method (LMM) from Gravity Recovery and Climate Experiment (GRACE) data. To assess TWS changes from LMM, different GRACE solutions, different hydrological models, and in situ data were used for validation. Results show that TWS changes from LMM in YRB has the best performance with the correlation coefficients of 0.80 and root mean square error of 1.48 cm in comparison with in situ data. The trend of TWS changes over the YRB increased by 10.39  1.27 Gt yr1 during the 20032015 period. Moreover, TWS change is disintegrated into the individual contributions of hydrological components (i.e., glaciers, surface water, soil moisture, and groundwater) from satellite data, hydrologic models, and in situ data. The estimated changes in individual TWS components in the YRB show that (1) the contribution of glaciers, surface water, soil moisture, and groundwater to total TWS changes is 15%, 12%, 25% and 48%, respectively; (2) Geladandong glacier melt from CryoSat-2/ICESat data has a critical effect on TWS changes with a correlation coefficients of 0.51; (3) the Three Gorges Reservoir Impoundment has a minimal effect on surface water changes (mainly lake water storage), but it has a substantial effect on groundwater storage (GWS), (4) the Poyang and Doting Lake water storage changes are mainly caused by climate change, (5) soil moisture storage change is mainly influenced by surface water, (6) human-induced GWS changes accounted for approximately half of the total GWS. The results of this study can provide valuable information for decision-making in water resources management.

Research areas: Land Surface/Agriculture Indicators
Additionality and Forest Conservation Regulation for Residential Development (2017)

AbstractWe analyze the potential effects that a unique forest conservation regulation has on residential development, and assess the additionality in forest cover due to this regulation. We combine panel data on forest cover change from satellite imagery and parcellevel modeling on residential development, including residential subdivisions occurring before and after the regulation is adopted. Our results suggest that after adoption, there was a 21% increase in forest cover within subdivisions relative to the amount without the regulation. The heterogeneous effects of this regulation suggest that on average, forest cover increased for parcels with lower levels of existing forest cover. However, parcels with the highest levels of forest cover continue to have significant decreases in forest cover, despite the regulation, thereby resulting in fragmentation in regions with the most intact forest cover.

Research areas: Habitat Conversion/Fragmentation
Application of Remote Sensing for Ex Ante Decision Support and Evaluating Impact (2020)

Deforestation is an environmental stressor that dramatically threatens biodiversity while having adverse, deep-rooted, socioeconomic impacts. Interventions to address deforestation require considerable long-term investments; therefore, assessing their impact is crucial. The UN Convention on Biological Diversity encourages establishing protected areas (PAs) as a strategy to conserve biodiversity, secure ecosystem services, support local livelihoods, and reduce climate change impacts. The Global Environment Facility (GEF) has supported the conservation and management of PAs, yet site accessibility and data availability present challenges in assessing PAs using traditional evaluation methods. We present a novel application of satellite Earth observations for evaluating the effectiveness and impact of PAs as a deforestation mitigation strategy. Geospatial analysis and ecological forecasting methodologies provide an efficient way to quantify land cover change, estimate above ground carbon stock, and evaluate ecosystem services provided by the PAs ex ante. We demonstrate the value of a geospatial approach through the evaluation of GEF-supported PAs in Kenya.

Research areas: Habitat Conversion/Fragmentation
Seasonal movements of Bronze Age transhumant pastoralists in western Xinjiang (2020)

The paper explores seasonal movements of Bronze Age mobile pastoralists in the western Tianshan mountainous region of Xinjiang, China. Fieldwork by a team from the Institute of Archaeology of the Chinese Academy of Social Science (CASS) and the University of Sydney, Australia have identified cyclical land use practices associated with the Andronovo cultural complex. Their pattern of seasonal movements has been reconstructed through ethnographic studies and analysis of modern snow and grass cover. Using this detailed combination of data, the study defines requirements for seasonal pastureswinter, summer and spring/autumnand shows a clear correlation between modern land use and seasonal patterns of movement in the Bronze Age.

Research areas: Habitat Conversion/Fragmentation
Australian fires 2019–2020: Tropospheric and stratospheric pollution throughout the whole fire season (2021)

The historically large and severe wildfires in Australia from September 2019 to March 2020 are known to have injected a smoke plume into the stratosphere around New Year, due to pyro-cumulonimbus (pyro-Cb) activity, that was subsequently distributed throughout the Southern Hemisphere (SH). We show with satellite, ground based remote sensing, and
              in situ
              observations that the fires before New Year, had already a substantial impact on the SH atmosphere, starting as early as September 2019, with subsequent long-range transport of trace gas plumes in the upper-troposphere. Airborne
              in situ
              measurements above Southern Argentina in November 2019 show elevated CO mixing ratios at an altitude of 11 km and can be traced back using FLEXPART trajectories to the Australian fires in mid-November 2019. Ground based solar-FTS (Fourier Transform Spectroscopy) observations of biomass burning tracers CO, HCN and C
              2
              H
              6
              at Lauder, South Island, New Zealand show enhanced tropospheric columns already starting in September 2019. In MLS observations averaged over 3060S, enhanced CO mixing ratios compared to previous years become visible in late October 2019 only at and below the 147 hPa pressure level. Peak differences are found with satellite and ground-based observations for all altitude levels in the Southern Hemisphere in January. With still increased aerosol values following the Ulawun eruption in 2019, averaged satellite observations show no clear stratospheric and upper-tropospheric aerosol enhancements from the Australian fires, before the pyro-Cb events at the end of December 2019. However, with the clear enhancement of fire tracers, we suggest the period September to December 2019 (prior to the major pyro-Cb events) should be taken into account in terms of fire pollutant emissions when studying the impact of the Australian fires on the SH atmosphere.

Research areas: Wildfires
New seasonal pattern of pollution emerges from changing North American wildfires (2022)

Rising emissions from wildfires over recent decades in the Pacific Northwest are known to counteract the reductions in human-produced aerosol pollution over North America. Since amplified Pacific Northwest wildfires are predicted under accelerating climate change, it is essential to understand both local and transported contributions to air pollution in North America. Here, we find corresponding increases for carbon monoxide emitted from the Pacific Northwest wildfires and observe significant impacts on both local and down-wind air pollution. Between 2002 and 2018, the Pacific Northwest atmospheric carbon monoxide abundance increased in August, while other months showed decreasing carbon monoxide, so modifying the seasonal pattern. These seasonal pattern changes extend over large regions of North America, to the Central USA and Northeast North America regions, indicating that transported wildfire pollution could potentially impact the health of millions of people.

Research areas: Wildfires
PFHydro: A new watershed-scale model for post-fire runoff simulation (2020)

Runoff increases after wildfires that burn vegetation and create a condition of soil-water repellence (SWR). A new post-fire watershed hydrological model, PFHydro, was created to explicitly simulate vegetation interception and SWR effects for four burn severity categories: high, medium, low severity and unburned. The model was applied to simulate post-fire runoff from the Upper Cache Creek Watershed in California, USA. NashSutcliffe modeling efficiency (NSE) was used to assess model performance. The NSE was 0.80 and 0.88 for pre-fire water years (WY) 2000 and 2015, respectively. NSE was 0.88 and 0.93 for WYs 2016 (first year post-fire) and 2017 respectively. The simulated percentage of surface runoff in total runoff of WY 2016 was about six times that of pre-fire WY 2000 and three times that of WY 2015. The modeling results suggest that SWR is an important factor for post-fire runoff generation. The model was successful at simulating SWR behavior.

Research areas: Wildfires
Wildfire combustion and carbon stocks in the southern Canadian boreal forest: Implications for a warming world (2020)

AbstractBoreal wildfires are increasing in intensity, extent, and frequency, potentially intensifying carbon emissions and transitioning the region from a globally significant carbon sink to a source. The productive southern boreal forests of central Canada already experience relatively high frequencies of fire, and as such may serve as an analog of future carbon dynamics for more northern forests. Firecarbon dynamics in southern boreal systems are relatively understudied, with limited investigation into the drivers of prefire carbon stocks or subsequent combustion. As part of NASA's ArcticBoreal Vulnerability Experiment, we sampled 79 stands (47 burned, 32 unburned) throughout central Saskatchewan to characterize above and belowground carbon stocks and combustion rates in relation to historical land use, vegetation characteristics, and geophysical attributes. We found southern boreal forests emitted an average of 3.3 1.1 kg C/m2 from field sites. The emissions from southern boreal stands varied as a function of stand age, fire weather conditions, ecozone, and soil moisture class. Sites affected by historical timber harvesting had greater combustion rates due to faster carbon stock recovery rates than sites recovering from wildfire events, indicating that different boreal forest land use practices can generate divergent carbon legacy effects. We estimate the 2015 fire season in Saskatchewan emitted a total of 36.3 15.0 Tg C, emphasizing the importance of southern boreal fires for regional carbon budgets. Using the southern boreal as an analog, the northern boreal may undergo fundamental shifts in forest structure and carbon dynamics, becoming dominated by stands <70 years old that hold 27 kg C/m2 less than current mature northern boreal stands. Our latitudinal approach reinforces previous studies showing that northern boreal stands are at a high risk of holding less carbon under changing disturbance conditions.

Research areas: Wildfires
Observed slump of sea land breeze in Brisbane under the effect of aerosols from remote transport during 2019 Australian mega fire events (2022)

Abstract. The 2019 Australian mega fires were unprecedented considering their intensity and consistency. There has been much research on the environmental and ecological effects of these mega fires, most of which focused on the effect of huge aerosol loadings and the ecological devastation. Sea land breeze (SLB) is a regional thermodynamic circulation closely related to coastal pollution dispersion, yet few have looked into how it is influenced by different types of aerosols transported from either nearby or remote areas. Mega fires provide an optimal scenario of large aerosol emissions. Near the coastal site of Brisbane Archerfield during January 2020, when mega fires were the strongest, reanalysis data from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) showed that mega fires did release huge amounts of aerosols, making aerosol optical depth (AOD) of total aerosols, black carbon (BC) and organic carbon (OC) approximately 240 %, 425 % and 630 % of the averages in other non-fire years. Using 20 years' wind observations of hourly time resolution from a global observation network managed by the National Oceanic and Atmospheric Administration (NOAA), we found that the SLB day number during that month was only 4, accounting for 33.3 % of the multi-years' average. The land wind (LW) speed and sea wind (SW) speed also decreased by 22.3 % and 14.8 % compared with their averages respectively. Surprisingly, fire spot and fire radiative power (FRP) analysis showed that heating effects and aerosol emission of the nearby fire spots were not the main causes of the local SLB anomaly, while the remote transport of aerosols from the fire centre was mainly responsible for the decrease of SW, which was partially offset by the heating effect of nearby fire spots and the warming effect of long-range transported BC and CO2. The large-scale cooling effect of aerosols on sea surface temperature (SST) and the burst of BC contributed to the slump of LW. The remote transport of total aerosols was mainly caused by free diffusion, while the large-scale wind field played a secondary role at 500 m. The large-scale wind field played a more important role in aerosol transport at 3 km than at 500 m, especially for the gathered smoke, but free diffusion remained the major contributor. The decrease of SLB speed boosted the local accumulation of aerosols, thus making SLB speed decrease further, forming a positive feedback mechanism.

Research areas: Wildfires
A comprehensive characterization of MODIS daily burned area mapping accuracy across fire sizes in tropical savannas (2021)

Daily global burned area mapping of Earth from remotely sensed data is of considerable interest and indicates a clear user need, despite well-known accuracy limitations. Many studies report global and regional indicators of spatial and temporal accuracy to evaluate the quality of burned area products, but tend to rely on relatively sparse validation data. In this paper, an extensive validation data set covering 223 million ha over the Brazilian Cerrado for the 2015 fire season is used to thoroughly evaluate how the accuracy of burned area products relying on distinct spectral channels (SWIR+NIR versus NIR) and spatial resolution (250 m, 500 m, and both) depends on fire size. Toward this end, we consider publicly available burned area products MCD64A1 (v006) at 500 m and FireCCI51 at 250 m and use a recently proposed graph-based patch algorithm, which is flexible enough to combine 250500 m bands. The trade-off between spatial resolution and spectral channels for the problem at hand reveals that better spatial resolution (NIR at 250 m) is preferable to a broader range of spectral channels (NIR + SWIR at 500 m) for small burns (<250 ha), but that this relation is not preserved for large burns (>1000 ha). Also, this study shows that combining both spectral indices into a single classifier leads to the most accurate burned area map. The analysis by land cover type indicates that overall accuracy is highest for grasslands and savannas, with grasslands benefiting the most from the use of SWIR bands. Results also indicate that burned areas can be classified with accuracy measured by the Dice Coefficient close to 80% for fire sizes larger than 500 ha, which corresponds to 60% of the total burned area, but accuracy lower than 36% for fire sizes smaller than 250 ha. In particular, our analysis suggests that the validation of burned area products always should be linked to the description of fire size distribution since it is a fundamental driver of accuracy. Results show that MODIS daily burned area mapping at 250500 m spatial resolution can exhibit high temporal accuracy, with almost unbiased estimates and standard deviation close to 1.5 days, indicating an accurate characterization of the spread of large fires.

Research areas: Wildfires
Seasonal Wildfire Outbreak Trend and its Consequences on Forest Biodiversity and the Environment: A Case Study of Sierra Leone (2021)

Sierra Leone is classified as a high wildfire risk country with a weather that support 50% chance of igniting wildfire especially from January to March each year. Wildfire outbreak in Sierra Leone has been having ecological, economic and health impacts on people and the environment over the years. This case study explores Sierra Leones wildfire outbreak trend, distribution, status, causes and consequences on biodiversity & the environment and proposed the way forward in tackling wildfire ignition, prevention and control methods in the near future. The daily active fire data from November 2000 to December 2019 were acquired from NASA MCD14DL product. Centroid vectors of fire events in 1 km by 1 km pixel were counted to give the total number of fire events in different administrative regions. Data was imported into the R Studio, version 4.0.3 from 2000-2019 for visualization and other graphical representation. The results show that the north-west and south-west experiences more wildfire incidence than other regions in Sierra Leone hence affecting the natural ecosystem. January to March was detected as the most wildfire prone months especially in the northern part of Sierra Leone. The results suggest that topography; climatic pattern and vegetation type has been considered a strong factor in influencing wildfire ignition over the years. The study concludes that the outdated 1924 fire prevention and control Act and climate change uncertainties are partially responsible for the frequent wildfire outbreak across Sierra Leone.

Research areas: Wildfires
Formaldehyde evolution in US wildfire plumes during the Fire Influence on Regional to Global Environments and Air Quality experiment (FIREX-AQ) (2021)

Abstract. Formaldehyde (HCHO) is one of the most abundant non-methane volatile organic compounds (VOCs) emitted by fires. HCHO also undergoes chemical production and loss as a fire plume ages, and it can be an important oxidant precursor. In this study, we disentangle the processes controlling HCHO by examining its evolution in wildfire plumes sampled by the NASA DC-8 during the Fire Influence on Regional to Global Environments and Air Quality experiment (FIREX-AQ) field campaign. In 9 of the 12 analyzed plumes, dilution-normalized HCHO increases with physical age (range 16 h). The balance of HCHO loss (mainly via photolysis) and production (via OH-initiated VOC oxidation) seems to control the sign and magnitude of this trend. Plume-average OH concentrations, calculated from VOC decays, range from 0.5 ( 0.5)  106 to 5.3 ( 0.7)  106 cm3. The production and loss rates of dilution-normalized HCHO seem to decrease with plume age. Plume-to-plume variability in dilution-normalized secondary HCHO production correlates with OH abundance rather than normalized OH reactivity, suggesting that OH is the main driver of fire-to-fire variability in HCHO secondary production. Analysis suggests an effective HCHO yield of 0.33 ( 0.05) per VOC molecule oxidized for the 12 wildfire plumes. This finding can help connect space-based HCHO observations to the oxidizing capacity of the atmosphere and to VOC emissions.

Research areas: Wildfires
High temporal resolution satellite observations of fire radiative power reveal link between fire behavior and aerosol and gas emissions (2020)

Wildfire smoke influences on air quality and atmospheric chemistry have been underscored by the increasing fire prevalence in recent years, and yet, the connection between fire, smoke emissions, and the subsequent transformation of this smoke in the atmosphere remains poorly constrained. Toward improving these linkages, we present a new method for coupling high time-resolution satellite observations of fire radiative power with in situ observations of smoke aerosols and trace gases. We apply this technique to 13 fire plumes comprehensively characterized during the recent FIREX-AQ mission and show that changes in fire radiative power directly translate into changes in conserved smoke tracers (CO<SUB>2</SUB>, CO, and black carbon aerosol) observed in the downwind smoke plume. The correlation is particularly strong for CO<SUB>2</SUB> (mean r &gt; 0.9). This method is important for untangling the competing effects of changing fire behavior versus the influence of dilution and atmospheric processing on the downwind evolution of measured smoke properties.

Research areas: Wildfires