Distribution of global drylands; areas with minimal vegetation and generally high water availability were masked out in white and grey, respectively. Source: ANU

Satellites provide invaluable services ranging from global communications links to a steady stream of data on environmental conditions that scientists can use to monitor various terrestrial ecosystems.

New applications for environmental monitoring from orbit are being explored, as exemplified by TEMPO, an instrument NASA designed in partnership with Ball Aerospace and Technologies Corporation. According to the agency, it will be the first space-based instrument to provide hourly daytime monitoring of major air pollutants across the North American continent.

Orbital tools can also be used to remotely gauge volcanic hazards. Intelligent sensor pods designed by University of Bristol, U.K., engineers to monitor volcanic activity for months at a time use a powerful wireless transmitter to send data to a base station with a satellite uplink at a safe distance of up to 10 km.

Now a research team from The Australian National University (ANU) has used new space technology to predict droughts and increased bushfire risk up to five months in advance. While most satellite observations of water availability are limited to either the surface or total water column, the method developed quantifies the vertical distribution of water storage.

The analysis combined assimilated data from several satellites to create a global ecohydrological model. This included: Moderate Resolution Imaging Spectroradiometer satellite instrument-derived surface water extent, Soil Moisture and Ocean Salinity near-surface soil moisture data, and Gravity Recovery and Climate Experiment total column water storage trends. The vertical distribution of water was then determined in different soil zones from the surface to the groundwater table.

The assimilation of satellite-observed water dynamics into the model makes estimating vegetation-accessible storage possible, providing insights into dryland ecology as well as a basis for seasonal drought impact forecasting. Case studies for southern California, the Horn of Africa and central Queensland, Australia, show that incorporating current soil water availability markedly improves the accuracy of vegetation condition forecasts three months in advance for most drylands. These forecasts can help improve drought early-warning systems and reduce economic and environmental impacts.

The research is published in Nature Communications.