Regional Climate Studies

Research in the Eltahir group seeks to improve our ability to simulate the climate of different regions around the world, with the goal of providing reliable prediction of climatic variables under changing conditions. To improve our simulation of the current climate, we focus on the processes that govern interactions between climate systems and land surface hydrology, vegetation and soil moisture at regional scales. Such interactions include:

(*) effects of dust emissions and irrigation, which are connected to human activities, on the climates of semi-arid and arid regions of Southwest Asia and West Africa; and
(*) diurnal processes related to surface characteristics, especially surface radiative heating, cumulus cloud cover and convective rainfall, and the contribution of such processes to the climate of the Maritime Continent.

Research in the Eltahir group also explores issues of climate and water resource management for one of the world’s most important watersheds – the Nile River basin. This work seeks to better quantify how available water resources will be affected by future climate change and how these resources might be most optimally divided amongst multiple and often competing users.

In all of these projects, observational data obtained from both remote sensing and ground stations are used to provide insight into the physical processes that drive regional climates. Numerical models act as pseudo-laboratories, allowing exploration of the complex feedback loops that exist between processes acting on scales ranging from tens to many thousands of kilometers.

Regional Climate Modeling of the Maritime Continent -- We are working to better understand the regional climate of the Maritime Continent, the patchwork of islands and oceans that constitutes the archipelago portion of Southeast Asia. Our work focuses on processes that occur at diurnal timescales, especially radiative heating, cumulus cloud formation and convective rainfall. These processes help shape the long-term climate of the entire Maritime Continent region and provide enormous inputs of heat and moisture to the upper troposphere, with implications for global atmospheric circulations.

Supporting Cooperation in the Nile Basin -- Ten countries fall within the drainage of the Nile Basin. As the nations compete for water rights, their relationships have deteriorated and the issues may escalate into conflict. The rapidly growing populations in the Nile Basin, 245 million in 1990, and projected to reach 859 million by 2025 (Wohl, 2011) may soon outstrip the water resources of the Nile. As the struggle for water continues, we investigate how we can best distribute the 84 km3 of water among competing needs like irrigation and hydropower, and nations like Sudan, Egypt and Ethiopia.

Studying Climate Change Impacts on the Nile Basin -- High levels of uncertainty in simulating the current and past hydrological cycle of the Nile basin using general circulation models (GCMs) creates a challenge for accurately estimating climate change impacts on the Nile basin. The objective of this project is to enhance our understanding of the hydroclimatology of the Nile Basin and to provide a more certain estimate of the climate change impacts on the hydrological cycle of the Nile basin.

Regional Climate Modeling over Semi-Arid Regions -- Blanketed by the Arabian Desert in the east and the Saharan desert in the west, many of the regions in Southwest Asia and West Africa can be described as semiarid or arid climatic regimes. The combination of a short, distinct rainy season with a long, hot, dry summer leads to a large strain on freshwater resources, providing strong motivation to study the climate of the area. More specifically, this work identifies the surface features over Southwest Asia and West Africa that dictate the surface climate. Particularly, this work focuses on the effects of two common surface processes in semi-arid climates: dust emissions and irrigation. Both of these land processes are influenced by human behavior and can have profound effects on regional climates. Consequently, to allow for the future assessment of climate variability over Southwest Asia and West Africa, this work presents a modified regional climate model that more accurately simulates the summertime climate over semiarid regions. Ultimately, this research strives to achieve a better understanding and prediction of the processes that determine the summertime climate of semiarid regions.