Yale CEO Environmental Monitoring in semi-arid
Central- and West-Asia (EMCWA):
Drivers and Trajectories
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Balkash Basin Syr-Darya / Chu Watershed Amu Darya Watershed

Study Area

The geographic focus of the EMCWA research project are the watersheds of  the Balkash Basin, the Syr-Darya / Chu rivers, the Amu-Darya river, and the rivers that discharge into the Caspian Sea.

 

   

Project Summary

Thematic emphasis is on ecological changes in semi-arid Central- and West-Asia, with the objective to investigate possibilities for a more meaningful, regional assessment of eco-system health from space. Though the primary interest is a regional one the results are intended to be detailed enough in order to be useful for local decision making. To explain any changes in eco-system health and their drivers, research effort is on vegetation, soils, climate, hydrology, and human activities. This will be achieved through various innovative techniques including a classifier that is sensitive to functional characteristics of vegetation or an algorithm that allows the separation of climate induced from subtle, human induced green biomass changes. Biophysical and hydro-meteorological characteristics described in the functional vegetation groups will be used in hydrologic modeling, to study the changes and the feedbacks between vegetation and hydrology.

The study focuses on the following major landscapes/land use areas:

  • Mountain areas, representing the most important source for river water,

  • cultivated areas, forming the main consumer of natural resources, particularly of irrigation water, and

  • the rangelands, which are often exposed to a growing pressure, imposed by the expansion of cultivation and/or by the intensification of animal grazing.

Spatial-temporal variations in resource availability and their impact on agricultural production and on agricultural strategies will be analyzed and projections be made under different climate change scenarios.

 

   

Functional Vegetation Groups and Vegetation Coverage

Understanding vegetation growing cycles and the functional characteristics that can be derived thereof are the key to a more meaningful, regional assessment of degradation processes as well as to a better parametrization of hydro-meteorological parameters.

To overcome limitations typically associated with conventional classifications of remotely sensed NDVI time series, we developed alternative cluster algorithms that are sensitive to characteristics associated with the plants phenology.

 

   

Degradation of Vegetation and Soils - Human / Climate?

Evidence for degradation processes in rangelands, including the reliable identification of its causes are a prerequisite for initiating effective counter-measures. This is particularly challenging in dry-land environments characterized by high inter-annual climate variation and a sometimes intense seasonal exploitation of its resources.

 Inter-annual climate fluctuations typically cause variations in rangeland vegetation covers that exceed those imposed by most human activities by a multiple. To reveal the subtle human induced vegetation changes - originating from overgrazing and fuel-wood cutting - the contribution of the climate signal to the vegetation cycle has to be removed.

 

   

Irrigated and Rainfed Agriculture

Limited availability of cultivable land and the demand for higher productivity is putting increasing pressure on agricultural areas. This also leads to the expansion of agricultural activities into the rarely suitable rangelands.

The trends and the impact of these developments will be investigated, particularly their significance for irrigation water demands, how they affect hydro-meteorologic parameters, the possible consequences for the environment, and what this could mean for the agriculture in the region. 

 

   

Climate and Hydrology

Anthropogenic and climate changes directly or indirectly impact the fresh water resources. Constructions like reservoirs or irrigation districts change fresh water use and its down-stream availability. Water availability and water withdrawal is strongly related to winter precipitation and summer temperature. With sometimes up to 80% of  river water derived from snow-fall (Syr Darya), adjacent mountain areas are of particular importance for water availability in the rivers.

Temperature anomaly trend for January between Longitude 40.0 to 65.0 and Latitude 50.0 to 30.0. The trend for Central Asia is 0.18oC/decade what is significantly higher than the global average (0.05oC/decade). (from NCDC Climate Monitoring)

 

 

 

Establishing the natural capacity of each watershed, including the seasonal and inter-annual variability, is required before anthropogenic impacts on the water resources can be assessed. This requires understanding and modeling the snow accumulation and melt processes in the region, particularly in the mountains. Through our Fourier Filtered Cycle Similarity Classification (FFCS), the study of climate sensitivities and identified trends in land cover/land use, we can parameterize the hydro-meteorologic parameters and make sound modifications to these parameters in future hydrologic change scenarios.

   

Project Information:

The EMCWA project is funded by NASA's Energy and Water Cycle Research Program (NEWS) as part of the NASA ESE Strategy, and is carried out at the Yale Center for Earth Observation. It started in November 2005 for a runtime of three years. With its focus on Central Asia this project is contributing to the Northern Eurasia Earth Science Partnership Initiative, NEESPI.