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Jason Beringer
,
Jorg Hacker
,
Lindsay B. Hutley
,
Ray Leuning
,
Stefan K. Arndt
,
Reza Amiri
,
Lutz Bannehr
,
Lucas A. Cernusak
,
Samantha Grover
,
Carol Hensley
,
Darren Hocking
,
Peter Isaac
,
Hizbullah Jamali
,
Kasturi Kanniah
,
Stephen Livesley
,
Bruno Neininger
,
Kyaw Tha Paw U
,
William Sea
,
Dennis Straten
,
Nigel Tapper
,
Richard Weinmann
,
Stephen Wood
, and
Steve Zegelin

Savannas are highly significant global ecosystems that consist of a mix of trees and grasses and that are highly spatially varied in their physical structure, species composition, and physiological function (i.e., leaf area and function, stem density, albedo, and roughness). Variability in ecosystem characteristics alters biophysical and biogeochemical processes that can affect regional to global circulation patterns, which are not well characterized by land surface models. We initiated a multidisciplinary field campaign called Savanna Patterns of Energy and Carbon Integrated across the Landscape (SPECIAL) during the dry season in Australian savannas to understand the spatial patterns and processes of land surface–atmosphere exchanges (radiation, heat, moisture, CO2, and other trace gasses). We utilized a combination of multiscale measurements including fixed flux towers, aircraft-based flux transects, aircraft boundary layer budgets, and satellite remote sensing to quantify the spatial variability across a continental-scale rainfall gradient (transect). We found that the structure of vegetation changed along the transect in response to declining average rainfall. Tree basal area decreased from 9.6 m2 ha−1 in the coastal woodland savanna (annual rainfall 1,714 mm yr−1) to 0 m2 ha−1 at the grassland site (annual rainfall 535 mm yr−1), with dry-season green leaf area index (LAI) ranging from 1.04 to 0, respectively. Leaf-level measurements showed that photosynthetic properties were similar along the transect. Flux tower measurements showed that latent heat fluxes (LEs) decreased from north to south with resultant changes in the Bowen ratios (H/LE) from a minimum of 1.7 to a maximum of 15.8, respectively. Gross primary productivity, net carbon dioxide exchange, and LE showed similar declines along the transect and were well correlated with canopy LAI, and fluxes were more closely coupled to structure than floristic change.

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Douglas J. Parker
,
Alan M. Blyth
,
Steven J. Woolnough
,
Andrew J. Dougill
,
Caroline L. Bain
,
Estelle de Coning
,
Mariane Diop-Kane
,
Andre Kamga Foamouhoue
,
Benjamin Lamptey
,
Ousmane Ndiaye
,
Paolo Ruti
,
Elijah A. Adefisan
,
Leonard K. Amekudzi
,
Philip Antwi-Agyei
,
Cathryn E. Birch
,
Carlo Cafaro
,
Hamish Carr
,
Benard Chanzu
,
Samantha J. Clarke
,
Helen Coskeran
,
Sylvester K. Danuor
,
Felipe M. de Andrade
,
Kone Diakaria
,
Cheikh Dione
,
Cheikh Abdoulahat Diop
,
Jennifer K. Fletcher
,
Amadou T. Gaye
,
James L. Groves
,
Masilin Gudoshava
,
Andrew J. Hartley
,
Linda C. Hirons
,
Ishiyaku Ibrahim
,
Tamora D. James
,
Kamoru A. Lawal
,
John H. Marsham
,
J. N. Mutemi
,
Emmanuel Chilekwu Okogbue
,
Eniola Olaniyan
,
J. B. Omotosho
,
Joseph Portuphy
,
Alexander J. Roberts
,
Juliane Schwendike
,
Zewdu T. Segele
,
Thorwald H. M. Stein
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Andrea L. Taylor
,
Christopher M. Taylor
,
Tanya A. Warnaars
,
Stuart Webster
,
Beth J. Woodhams
, and
Lorraine Youds

Abstract

Africa is poised for a revolution in the quality and relevance of weather predictions, with potential for great benefits in terms of human and economic security. This revolution will be driven by recent international progress in nowcasting, numerical weather prediction, theoretical tropical dynamics, and forecast communication, but will depend on suitable scientific investment being made. The commercial sector has recognized this opportunity and new forecast products are being made available to African stakeholders. At this time, it is vital that robust scientific methods are used to develop and evaluate the new generation of forecasts. The Global Challenges Research Fund (GCRF) African Science for Weather Information and Forecasting Techniques (SWIFT) project represents an international effort to advance scientific solutions across the fields of nowcasting, synoptic and short-range severe weather prediction, subseasonal-to-seasonal (S2S) prediction, user engagement, and forecast evaluation. This paper describes the opportunities facing African meteorology and the ways in which SWIFT is meeting those opportunities and identifying priority next steps. Delivery and maintenance of weather forecasting systems exploiting these new solutions requires a trained body of scientists with skills in research and training, modeling and operational prediction, and communications and leadership. By supporting partnerships between academia and operational agencies in four African partner countries, the SWIFT project is helping to build capacity and capability in African forecasting science. A highlight of SWIFT is the coordination of three weather forecasting “Testbeds”—the first of their kind in Africa—which have been used to bring new evaluation tools, research insights, user perspectives, and communications pathways into a semioperational forecasting environment.

Open access