OOSKAnews Voices: Real-Time Precipitation Estimates in Data-Sparse Regions

23 Feb 2016 by OOSKAnews Correspondent
ALEXANDRIA, VA, United States

OOSKAnews Voices is a new series of guest “opinion columns” on water, written by senior participants in different parts of the international water community. The columns provide a global platform for organizations and individuals to promulgate their views and messages.

In this piece, William S Logan, PhD, Deputy Director of the International Center for Integrated Water Resources Management (ICIWaRM), discusses the tools being developed to help individuals and water managers in developing countries with precipitation estimation and flood and drought monitoring and forecasting.


In 2009, Logan was Science Attaché for the US Mission to UNESCO in Paris, handling fresh water, oceans, climate change, and the basic sciences. From 1999-2008, he was Staff Officer and Senior Staff Officer at the Water Science and Technology Board of the National Research Council, directing studies related to large-scale watershed restoration, managed aquifer recharge, river science, space-based and in-situ sensor technology, and biofuels.  Formerly, he was Assistant Professor of Hydrogeology at The George Washington University, and Assistant to the President for the Association of Geoscientists for International Development (AGID).

He serves on the Board of Directors of Aqua-LAC, the Journal of UNESCO IHP for Latin America and the Caribbean, and on the Governing Board of the Centro del Agua para Zonas Áridas y Semiáridas de América Latina y el Caribe (CAZALAC) in La Serena, Chile.

Let’s say you’re a water manager in a country whose perennial rivers are international, with their origin outside of the country. International data-sharing is limited or time-lagged. Regional weather reports had suggested the potential for heavy rains in a basin’s headwaters. But how much rain fell? Are your downstream citizens in danger? Should they get ready to plant their crops?

Or perhaps you are a scientist, engineer, or even a farmer or a backpacker out in the field, hours from a major city. You’ve got a smartphone and some decent connectivity. You see thunderstorms on the horizon. Again, what’s going on there that may affect your safety or your livelihood? How can you get some information quickly?

In developed countries, a surfeit of data is flooding in from land-based weather stations, weather balloons, Doppler radar stations and weather satellites. Supercomputers are busily at work crunching the data and doing numerical weather prediction. Real-time rainfall estimates are easy to find, whether you are sitting at a desktop computer or accessing a mobile app from a smart phone or tablet.

But perhaps you find yourself in a country with a small fraction of such resources, and a fraction of that fraction generating accurate, actionable information in real time. Now what?

The United Nations Educational, Scientific and Cultural Organization’s (UNESCO) International Hydrological Program (IHP) has been working hard to address such needs. Primarily through its G-WADI program, IHP and its partners have developed a variety of tools related to precipitation estimation, as well as flood and drought monitoring and forecasting.

In the first case above, rainfall estimates from the G-WADI PERSIANN-CCS GeoServer could prove useful. The GeoServer harnesses remotely sensed information to observe, monitor and analyze extreme weather events as they occur. At its heart is a real-time (with about one hour delay), global (60°N to 60°S), high-resolution (approximately 4-kilometer), satellite-based precipitation product produced by the University of California-Irvine’s Center for Hydrometeorology and Remote Sensing (CHRS).

The mapping and visualization software is open source and user friendly; you can zoom in and out for the scale that is of best use to you. And this information is displayed even in remote areas and over oceans where observations are limited.

PERSIANN-CCS is beginning to be used operationally, for example, by the Namibian National Hydrological Services (NHS) of the Ministry of Agriculture, Water and Forestry. PERSIANN-CCS information assists the NHS in making more accurate judgments about future water supply for multiple uses, and provides early warnings for floods and droughts in areas located in its national and trans-boundary river basins. In countries in South America, Africa and East and Southeast Asia, G-WADI-linked projects are under way to evaluate possible applications of real-time precipitation information.

For our scientist or farmer in the field with access to a mobile network, there is a version of G-WADI PERSIANN-CCS for iOS- and Android-based devices called RainMapper that can be freely downloaded from the App Store and Google Play. With an option to display intervals from three- to 72-hour totals, applications range from flash-flood warnings to when to plant rain-fed crops.

While complete weather reports and forecasts remain the ideal, often an estimate of how much rain has fallen recently in or around the area of interest is sufficient -- and certainly better than no information at all.

Additional products are available or under development by G-WADI and others. It would seem that we are on the cusp of an era where such tools can be tested and calibrated for sub-regional or local conditions, and increasing used to augment, rather than replace, in-situ information.