Drought characterization on the Navajo Nation via a web-based remote sensing tool

In data scarce regions of the world, remote sensing can provide the data needed to support ground-based monitoring systems. On the Navajo Nation, the largest federally recognized tribe in land area, of over 70,000 km 2 , there are many challenges related to water management during long-term drought. Currently, the Navajo Nation Department of Water Resources (NNDWR) reports on drought and climatic conditions through the use of regional Standardized Precipitation Index (SPI) values and a network of in-situ rainfall and climate data. However, these data sources lack the spatial detail and consistent measurements needed to provide a coherent understanding of the drought regime within the Nation's boundaries. This project has created a cloud-based web application, the Drought Severity Evaluation Tool (DSET), for improved drought reporting that will integrate remotely-sensed, modeled, and in-situ data on the NN. This tool harnesses the capabilities of Google Earth Engine (GEE), specifically through a partnership with the Desert Research Institute (DRI) and ClimateEngine.org, to conduct drought and land assessments. DSET integrates NASA and USGS Earth Observations (i.e. TRMM, GPM, Landsat, MODIS), modeled climate data (i.e. CHIRPS and gridMET), and in-situ rain gauge data for on-the-fly analyses. DSET computing capabilities includes the generation of regional to field scale maps, time series figures, and reporting metrics that can assist in drought emergency declarations and the subsequent allocation of relief dollars across the NN.