Using techniques from astrophysics, researchers can forecast drought up to ten weeks ahead

July 20, 2020

Researchers at the University of Sussex have developed a system which can accurately predict a period of drought in East Africa up to ten weeks ahead.

Satellite imagery is already used in Kenya to monitor the state of pastures and determine the health of the vegetation using a metric known as the Vegetation Condition Index. These are conveyed to the decision makers in arid and semi-arid regions of Kenya through drought early warning systems.

However, these systems, operated by the National Drought Management Authority (NDMA), only allows organisations and communities to intervene when the impacts of a drought have already occurred. By that point, such extreme weather would already have had a devastating effect on the livelihood of local people.

Instead, a team of researchers from the University of Sussex and the NDMA have developed a new system called Astrocast.

Part-funded by the Science and Technology Facilities Council, the project allows humanitarian agencies and drought risk managers to be proactive when it comes to dealing with the impacts of extreme weather by forecasting changes before they occur.

In a research paper published in Remote Sensing of Environment, they explain how an interdisciplinary team of data scientists (astronomers and mathematicians) with geographers used techniques from astronomy science; processing data directly from space telescopes before using advance statistical methods to forecast extreme weather.

Dr Pedram Rowhani, Senior Lecturer in Geography and co-founder of Astrocast, said: "In many cases, the first signs of a drought can be seen on natural vegetation, which can be monitored from space.

"Our approach measures past and present Vegetation Condition Index (VCI), an indicator that is based on satellite imagery and often used to identify drought conditions, to understand trends and the general behaviour of the VCI over time, to predict what may happen in the future."

Joint first author on the paper and Lecturer in Machine Learning and Data Science, Dr Adam Barrett said: "After conversations in corridors with Dr Rowhani about AstroCast, I saw an opportunity to apply methodology I'd been developing in theoretical neuroscience to a project with potential for real humanitarian impact.

"With Sussex actively encouraging interdisciplinary working, we decided to combine skillsets. It's been eye-opening to see how our techniques can be applied to a real-world problem and improve lives."

There has been a growing demand within the humanitarian sector to develop systems that focus on advance warnings and encourage a more proactive approach to disasters.

The Kenyan NDMA already provides monthly drought bulletins for every county, which state detected changes in the vegetation and are used to make decisions about whether to declare a drought alert.

But with Astrocast forecasts, these bulletins could also include a prediction of what the VCI is likely to be in a few weeks' time, giving farmers and pastoralist valuable time to prepare.

Seb Oliver, Professor of Astrophysics and co-founder of Astrocast, said: "A large part of my astrophysics research requires processing data from astronomical space telescopes, like the Herschel Space Observatory. Earth observation satellites are not that different.

"We often use cutting-edge statistics and machine-learning approaches to interpret our astronomical data. In this case we've used machine-learning approaches, and we've been able to forecast the state of the vegetation up to ten weeks ahead with very good confidence.

"We imagine that our reports might be used to define a new warning flag allowing county leaders to make decisions earlier and so prepare better. But this information could also be used by humanitarian organisations like the Kenya Red Cross as well as other organisations like the Kenya Met Department.

"Earlier preparation is well known to be much more effective than reactive response."
The work is part of a larger research project under the Science for Humanitarian Emergencies and Resilience (SHEAR) programme, which looks to understand how forecasts can be used by disaster risk managers to act early in order to minimise the impacts of disasters.

Moving forward, they hope to improve their existing system to provide forecasts over a much larger region while providing more on-the-ground training for a variety of other organisations in Kenya and beyond.

University of Sussex

Related Drought Articles from Brightsurf:

Redefining drought in the US corn belt
As the climate trends warmer and drier, global food security increasingly hinges on crops' ability to withstand drought.

The cost of drought in Italy
Drought-induced economic losses ranged in Italy between 0.55 and 1.75 billion euros over the period 2001-2016, and droughts caused significant collateral effects not only on the agricultural sector, but also on food manufacturing industries.

Consequences of the 2018 summer drought
The drought that hit central and northern Europe in summer 2018 had serious effects on crops, forests and grasslands.

Songbirds reduce reproduction to help survive drought
New research from the University of Montana suggests tropical songbirds in both the Old and New Worlds reduce reproduction during severe droughts, and this - somewhat surprisingly -- may actually increase their survival rates.

Predicting drought in the American West just got more difficult
A new, USC-led study of more than 1,000 years of North American droughts and global conditions found that forecasting a lack of precipitation is rarely straightforward.

Where is the water during a drought?
In low precipitation periods - where and how is the limited available water distributed and what possibilities are there for improving retention in the soil and the landscape?

What does drought mean for endangered California salmon?
Droughts threatens California's endangered salmon population -- but pools that serve as drought refuges could make the difference between life and death for these vulnerable fish.

With shrinking snowpack, drought predictability melting away
New research from CU Boulder suggests that during the 21st century, our ability to predict drought using snow will literally melt away.

An evapotranspiration deficit drought index to detect drought impacts on ecosystems
The difference between actual and potential evapotranspiration, technically termed a standardized evapotranspiration deficit drought index (SEDI), can more sensitively capture the biological changes of ecosystems in response to the dynamics of drought intensity, compared with indices based on precipitation and temperature.

Sesame yields stable in drought conditions
Research shows adding sesame to cotton-sorghum crop rotations is possible in west Texas

Read More: Drought News and Drought Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to