scholarly journals Regional Climatological Drought: An Assessment Using High-Resolution Data

Hydrology ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 33 ◽  
Author(s):  
Alen Shrestha ◽  
Md Mafuzur Rahaman ◽  
Ajay Kalra ◽  
Balbhadra Thakur ◽  
Kenneth W. Lamb ◽  
...  
Keyword(s):  
High Resolution ◽  
Distribution Systems ◽  
Potential Evapotranspiration ◽  
Spatial Scales ◽  
Regional Scale ◽  
Drought Severity ◽  
Climate Data ◽  
Drought Analysis ◽  
High Resolution Data ◽  
Spatial And Temporal Scales

Regional assessments of droughts are limited, and meticulous assessments over larger spatial scales are generally not substantial. Understanding drought variability on a regional scale is crucial for enhancing the resiliency and adaptive ability of water supply and distribution systems. Moreover, it can be essential for appraising the dynamics and projection of droughts based on regional climate across various spatial and temporal scales. This work focuses on drought analysis using a high-resolution dataset for three drought-prone regions of India between 1950 and 2016. This study also uses monthly values of the self-calibrating Palmer Drought Severity Index (scPDSI), incorporating Penman–Monteith approximation, which is physically based on potential evapotranspiration. Climate data are statistically downscaled and formulated to form a timeline for characterizing major drought events. The downscaled climate data hold a good statistical agreement with station data with correlation coefficients (R) ranging from 0.91 to 0.96. Drought analysis indicates and identifies several major incidences over the analysis time period considered in this work, which truly adheres to the droughts recorded in reports of various literatures for those regions.

Insights from a New High-Resolution Drought Atlas for the Caribbean Spanning 1950–2016

2017 ◽  
Vol 30 (19) ◽  
pp. 7801-7825 ◽  
Author(s):  
Dimitris Herrera ◽  
Toby Ault
Keyword(s):  
High Resolution ◽  
Potential Evapotranspiration ◽  
Caribbean Region ◽  
Drought Severity ◽  
Time Interval ◽  
Spatial And Temporal Scales ◽  
Adaptation Capacity ◽  
Drought Variability ◽  
Drought Prediction ◽  
The Caribbean

Abstract Climate change is expected to increase the severity and frequency of drought in the Caribbean. Understanding drought variability and its trends is therefore critical for improving resiliency and adaptation capacity of this region, as well as for assessing the dynamics and predictability of regional hydroclimate across spatial and temporal scales. This work introduces a first of its kind high-resolution drought dataset for the Caribbean region from 1950 to 2016, using monthly estimates of the “self calibrating” Palmer drought severity index (scPDSI), with the physically based Penman–Monteith approximation for the potential evapotranspiration. Statistically downscaled data products, including reanalysis, are employed to establish an historical baseline for characterizing drought from 1950 to the near present. Since 1950, the Caribbean has been affected by severe droughts in 1974–77, 1997/98, 2009/10, and 2013–16. Results indicate that the 2013–16 drought is the most severe event during the time interval analyzed in this work, which agrees with qualitative reports of many meteorological institutions across the Caribbean. Linear trends in the scPDSI show a significant drying in the study area, averaging an scPDSI change of −0.09 decade−1 (p < 0.05). However, this trend is not homogenous, and significant trends toward wetter conditions in portions of the study area were observed. Results further indicate a strong influence of both tropical Pacific and North Atlantic oceans in modulating drought variability across the study domain. Finally, this effort is the first step in building high-resolution drought products for the Caribbean to be updated regularly, with the purpose of drought monitoring and eventually seasonal drought prediction.

scholarly journals Mapping Coastal Wetland Biomass from High Resolution Unmanned Aerial Vehicle (UAV) Imagery

2019 ◽  
Vol 11 (5) ◽  
pp. 540 ◽  
Author(s):  
Cheryl Doughty ◽  
Kyle Cavanaugh
Keyword(s):  
Salt Marsh ◽  
High Resolution ◽  
Aboveground Biomass ◽  
Vegetation Index ◽  
Coastal Wetland ◽  
Spatial Scales ◽  
Biomass Estimation ◽  
Spatial And Temporal Variability ◽  
Estimation Model ◽  
Spatial And Temporal Scales

Salt marsh productivity is an important control of resiliency to sea level rise. However, our understanding of how marsh biomass and productivity vary across fine spatial and temporal scales is limited. Remote sensing provides a means for characterizing spatial and temporal variability in marsh aboveground biomass, but most satellite and airborne sensors have limited spatial and/or temporal resolution. Imagery from unmanned aerial vehicles (UAVs) can be used to address this data gap. We combined seasonal field surveys and multispectral UAV imagery collected using a DJI Matrice 100 and Micasense Rededge sensor from the Carpinteria Salt Marsh Reserve in California, USA to develop a method for high-resolution mapping of aboveground saltmarsh biomass. UAV imagery was used to test a suite of vegetation indices in their ability to predict aboveground biomass (AGB). The normalized difference vegetation index (NDVI) provided the strongest correlation to aboveground biomass for each season and when seasonal data were pooled, though seasonal models (e.g., spring, r2 = 0.67; RMSE = 344 g m−2) were more robust than the annual model (r2 = 0.36; RMSE = 496 g m−2). The NDVI aboveground biomass estimation model (AGB = 2428.2 × NDVI + 120.1) was then used to create maps of biomass for each season. Total site-wide aboveground biomass ranged from 147 Mg to 205 Mg and was highest in the spring, with an average of 1222.9 g m−2. Analysis of spatial patterns in AGB demonstrated that AGB was highest in intermediate elevations that ranged from 1.6–1.8 m NAVD88. This UAV-based approach can be used aid the investigation of biomass dynamics in wetlands across a range of spatial scales.

Processes, Products & Policy: Investigating how drought events are perceived differently across spatial scales

2020 ◽  
Author(s):  
Josie Baulch ◽  
Justin Sheffield ◽  
Jadu Dash
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Sub Saharan Africa ◽  
Scaling Analysis ◽  
Technological Advancement ◽  
High Resolution Data ◽  
New Era ◽  
Drought Assessment ◽  
Satellite Technology ◽  
Sub Saharan

<p>Traditionally, availability of consistent, high quality, high-resolution data for Sub-Saharan Africa (SSA) has been limited, with political barriers, poverty and slow technological advancement all contributing to this issue. Over the past 30 years, a rapid increase in the advancement of satellite technology has led to the new era of ‘big data’, which includes a number of high-resolution, global remote sensing datasets. With an overwhelming amount of data now being downloaded and processed, we need to be sure that the best products are being used, in the most appropriate way, to determine the onset and evolution of extreme hydrological events and to influence policy implementation. This study uses scaling analysis of a number of hydrological and agricultural variables to investigate how spatial resolution influences monitoring of drought events. By studying the 2016/17 drought in Kenya, and assessing the drought footprint at various resolutions, it is evident that the data and its scale largely influences the apparent drought signal. Across all the variables, coarser data showed a significantly reduced drought extent than finer data, with a number of regions appearing to not fall below the drought threshold, when in reality, that area was experiencing drought. The implications of these scale issues could be significant, as drought policies in Kenya are implemented on a county level basis. By understanding the importance of effective scaling between the decision-making scale (policy), the data used for drought assessment (products) and the impacts of drought on the ground (processes), updated drought management and mitigation techniques can be used, with potential to reduce vulnerability to future drought events.</p>

HRSC-A data: a new high-resolution data set with multipurpose applications in physical geography

2007 ◽  
Vol 31 (2) ◽  
pp. 179-197 ◽  
Author(s):  
J.-C. Otto ◽  
K. Kleinod ◽  
O. König ◽  
M. Krautblatter ◽  
M. Nyenhuis ◽  
...  
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
Research Training ◽  
Spatial Scales ◽  
Three Dimensional ◽  
Physical Geography ◽  
Vegetation Monitoring ◽  
Data Set ◽  
High Resolution Data ◽  
Resolution Data

The analysis and interpretation of remote sensing data facilitates investigation of land surface complexity on large spatial scales. We introduce here a geometrically high-resolution data set provided by the airborne High Resolution Stereo Camera (HRSC-A). The sensor records digital multispectral and panchromatic stereo bands from which a very high-resolution ground elevation model can be produced. After introducing the basic principles of the HRSC technique and data, applications of HRSC data within the multidisciplinary Research Training Group 437 are presented. Applications include geomorphologic mapping, geomorphometric analysis, mapping of surficial grain-size distribution, rock glacier kinematic analysis, vegetation monitoring and three-dimensional landform visualization. A final evaluation of the HRSC data based on three years of multipurpose usage concludes this presentation. A combination of image and elevation data opens up various possibilities for visualization and three-dimensional analysis of the land surface, especially in geomorphology. Additionally, the multispectral imagery of the HRSC data has potential for land cover mapping and vegetation monitoring. We consider HRSC data a valuable source of high-resolution terrain information with high applicability in physical geography and earth system science.

WATZON: the Italian network of ecohydrology and critical zone observatories 

2021 ◽  
Author(s):  
Marco Borga ◽  
Daniele Penna ◽  
Nasta Paolo ◽  
Comiti Francesco ◽  
Stefano Ferraris ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Critical Zone ◽  
Catchment Scale ◽  
Data Set ◽  
Near Surface ◽  
High Resolution Data ◽  
Water Mixing ◽  
Study Sites ◽  
Scientific Questions

<p>The Italian initiative WATZON (WATer mixing in the critical ZONe) is a network of instrumented sites, bringing together six pre-existing long-term research observatories monitoring different compartments of the Critical Zone - the Earth's permeable near-surface layer from the tops of the trees to the bottom of the groundwater.  These observatories cover different climatic and physiographic characteristics over the country, providing information over a climate and eco-hydrologic transect connecting the Mediterranean to the Alps. With specific initial scientific questions, monitoring strategies, databases, and modeling activities, the WATZON observatories and sites is well representative of the heterogeneity of the critical zone and of the scientific communities studying it. Despite this diversity, all WATZON sites share a common eco-hydrologic monitoring and modelling program with three main objectives:</p><p>1) assessing the description of water mixing process across the critical zone by using integrated high-resolution isotopic, geophysical and hydrometeorological measurements from point to catchment scale, under different physiographic conditions and climate forcing;</p><p>2) testing water exchange mechanisms between subsurface reservoirs and vegetation, and assessing ecohydrological dynamics in different environments by coupling the high-resolution data set from different critical zone study sites of the initiative with advanced ecohydrological models at multiple spatial scales;</p><p>3) developing a process-based conceptual framework of ecohydrological processes in the critical zone to translate scientific knowledge into evidence to support policy and management decisions concerning water and land use in forested and agricultural ecosystems.</p><p>This work provides an overview of the WATZON network, its objectives, scientific questions, and data management, with a specific focus on existing initiatives for linking data and models based on WATZON data.</p><p> </p>

scholarly journals Tracking Interannual Streamflow Variability with Drought Indices in the U.S. Pacific Northwest

2014 ◽  
Vol 15 (5) ◽  
pp. 1900-1912 ◽  
Author(s):  
John T. Abatzoglou ◽  
Renaud Barbero ◽  
Jacob W. Wolf ◽  
Zachary A. Holden
Keyword(s):  
Pacific Northwest ◽  
Potential Evapotranspiration ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
The United States ◽  
Drought Indices ◽  
Drought Severity ◽  
Climate Data ◽  
Mountain Watersheds ◽  
Streamflow Variability

Abstract Drought indices are often used for monitoring interannual variability in macroscale hydrology. However, the diversity of drought indices raises several issues: 1) which indices perform best and where; 2) does the incorporation of potential evapotranspiration (PET) in indices strengthen relationships, and how sensitive is the choice of PET methods to such results; 3) what additional value is added by using higher-spatial-resolution gridded climate layers; and 4) how have observed relationships changed through time. Standardized precipitation index, standardized precipitation evapotranspiration index (SPEI), Palmer drought severity index, and water balance runoff (WBR) model output were correlated to water-year runoff for 21 unregulated drainage basins in the Pacific Northwest of the United States. SPEI and WBR with time scales encompassing the primary precipitation season maximized the explained variance in water-year runoff in most basins. Slightly stronger correlations were found using PET estimates from the Penman–Monteith method over the Thornthwaite method, particularly for time periods that incorporated the spring and summer months in basins that receive appreciable precipitation during the growing season. Indices computed using high-resolution climate surfaces explained over 10% more variability than metrics derived from coarser-resolution datasets. Increased correlation in the latter half of the study period was partially attributable to increased streamflow variability in recent decades as well as to improved climate data quality across the interior mountain watersheds.

scholarly journals Climate change, re-/afforestation, and urbanisation impacts on evapotranspiration and streamflow in Europe

2019 ◽  
Author(s):  
Adriaan J. Teuling ◽  
Emile de Badts ◽  
Femke A. Jansen ◽  
Richard Fuchs ◽  
Joost Buitink ◽  
...  
Keyword(s):  
Land Use ◽  
High Resolution ◽  
Large Scale ◽  
Forest Cover ◽  
Potential Evapotranspiration ◽  
Regional Scale ◽  
Large River ◽  
Climate Conditions ◽  
Continental Scale ◽  
The 1950S

Abstract. Since the 1950s, Europe has seen large shifts in climate and land cover. Previous assessments of past and future changes in evapotranspiration or streamflow have either focussed on land use/cover or climate contributions, or have focussed on individual catchments under specific climate conditions. Here, we aim to understand how decadal changes in climate (e.g., precipitation, temperature) and land use (e.g., de-/afforestation, urbanization) have impacted the amount and distribution of water resources availability across Europe since the 1950s. To this end, we simulate the distribution of green and blue water fluxes at high-resolution (1 × 1 km) by combining (a) a steady-state Budyko model for water balance partitioning constrained by long-term (lysimeter) observations across different land-use types, (b) a novel decadal high-resolution historical land use reconstruction, and (c) gridded observations of key meteorological variables. The continental-scale patterns in the simulations agree well with coarser-scale observation-based estimates of evapotranspiration, and also with observed changes in streamflow from small basins across Europe. We find that strong shifts in the continental-scale patterns of evapotranspiration and streamflow have occured from 1950 to 2010. In Sweden, for example, increased precipitation dominates effects of large scale re- and afforestation leading to increases in both streamflow and evapotranspiration. In most of the Mediterrenean, decreased precipitation combines with increased forest cover and potential evapotranspiration to reduce streamflow. In spite of local and regional scale complexity, the Europe-wide net contribution of land use, precipitation and potential evapotranspiration changes to changes in ET is similar with around ~ 40 km3/y, equivalent to the discharge of a large river. For streamflow, changes in precipitation dominate land use and potential evapotranspiration contributions with ~ 90 km3/y compared to ~ 45 km3/y. Locally, increased forest cover and urbanisation have lead to significant decreases and increases of available streamflow.

scholarly journals Climate Explorer: Improved Access to Local Climate Projections

2020 ◽  
Vol 101 (3) ◽  
pp. E265-E273
Author(s):  
Fredric Lipschultz ◽  
David D. Herring ◽  
Andrea J. Ray ◽  
Jay R. Alder ◽  
LuAnn Dahlman ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Easy Access ◽  
Climate Projections ◽  
Climate Data ◽  
Local Climate ◽  
Climate Conditions ◽  
Spatial And Temporal Scales ◽  
Climate Resilience ◽  
Projected Changes ◽  
The U.S

Abstract The goal of the U.S. Climate Resilience Toolkit’s (CRT) Climate Explorer (CE) is to provide information at appropriate spatial and temporal scales to help practitioners gain insights into the risks posed by climate change. Ultimately, these insights can lead to groups of local stakeholders taking action to build their resilience to a changing climate. Using CE, decision-makers can visualize decade-by-decade changes in climate conditions in their county and the magnitude of changes projected for the end of this century under two plausible emissions pathways. They can also check how projected changes relate to user-defined thresholds that represent points at which valued assets may become stressed, damaged, or destroyed. By providing easy access to authoritative information in an elegant interface, the Climate Explorer can help communities recognize—and prepare to avoid or respond to—emerging climate hazards. Another important step in the evolution of CE builds on the purposeful alignment of the CRT with the U.S. Global Change Research Program’s (USGCRP) National Climate Assessment (NCA). By closely linking these two authoritative resources, we envision that users can easily transition from static maps and graphs within NCA reports to dynamic, interactive versions of the same data within CE and other resources within the CRT, which they can explore at higher spatial scales or customize for their own purposes. The provision of consistent climate data and information—a result of collaboration among USGCRP’s federal agencies—will assist decision-making by other governmental entities, nongovernmental organizations, businesses, and individuals.

scholarly journals Maize yield and rainfall on different spatial and temporal scales in Southern Brazil

2007 ◽  
Vol 42 (5) ◽  
pp. 603-613 ◽  
Author(s):  
Homero Bergamaschi ◽  
Timothy Robert Wheeler ◽  
Andrew Juan Challinor ◽  
Flávia Comiran ◽  
Bruna Maria Machado Heckler
Keyword(s):  
Spatial Scales ◽  
Regional Scale ◽  
Daily Rainfall ◽  
Grain Filling ◽  
Maize Yield ◽  
Reproductive Period ◽  
Spatial And Temporal Scales ◽  
Crop Monitoring ◽  
Crop Cycle ◽  
Temporal And Spatial

This study aimed to establish relationships between maize yield and rainfall on different temporal and spatial scales, in order to provide a basis for crop monitoring and modelling. A 16-year series of maize yield and daily rainfall from 11 municipalities and micro-regions of Rio Grande do Sul State was used. Correlation and regression analyses were used to determine associations between crop yield and rainfall for the entire crop cycle, from tasseling to 30 days after, and from 5 days before tasseling to 40 days after. Close relationships between maize yield and rainfall were found, particularly during the reproductive period (45-day period comprising the flowering and grain filling). Relationships were closer on a regional scale than at smaller scales. Implications of the crop-rainfall relationships for crop modelling are discussed.

scholarly journals Reproductive success of Eastern Bluebirds (Sialia sialis) varies with the timing and severity of drought

2019 ◽  
Author(s):  
Reneé E. Carleton ◽  
John H. Graham ◽  
Adel Lee ◽  
Zachary P. Taylor ◽  
Jon F. Carleton
Keyword(s):  
Reproductive Success ◽  
Spatial Scales ◽  
Vegetation Indices ◽  
Drought Severity ◽  
Climate Data ◽  
Sialia Sialis ◽  
Eastern Bluebird ◽  
Governmental Agencies ◽  
Eastern Bluebirds ◽  
Clutch Initiation

AbstractDrought affects avian communities in complex ways. We used our own and citizen science-generated reproductive data acquired through The Cornell Lab of Ornithology’s NestWatch Program, combined with drought and vegetation indices obtained from governmental agencies, to determine drought effects on Eastern Bluebird (Sialia sialisL.) reproduction across their North American breeding range for the years 2006–2013. Our results demonstrate that some aspects of bluebird reproductive success varies with the timing and severity of drought. Clutch size was unaffected by drought occurrence or severity during or within one and two months of clutch initiation, but hatching and fledging rates decreased as drought severity increased. Drought conditions occurring one month prior to the month during which eggs should have hatched, and two months prior to the month nestlings should have fledged also reduced the numbers of fledged offspring. We also demonstrate the value of datasets generated by citizen scientists in combination with climate data for examining biotic responses at large temporal and spatial scales.

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