World Water and Climate Atlas

Transcription

1 International Water Management Institute World Water and Climate Atlas Direct access to water and climate data improves agricultural planning The IWMI World Water and Climate Atlas provides rapid access to the global climate data needed to understand and solve many of the world s water scarcity and food security problems. Using the Atlas, irrigation and agricultural planners can answer questions such as: Where can rainfed agriculture be expanded? Where can supplemental irrigation increase crop yields? Where is irrigation essential for viable agriculture? How much irrigation do crops need in relation to what the climate provides? What areas are suitable for specific crops in terms of maximum and minimum temperatures and other climatic variables? Where should an irrigation scheme be sited? What is the potential for water harvesting? þ A view of annual precipitation and reference evapotranspiration rates. How much water is entering a river basin system through rainfall, and how much is leaving through evaporation and plant transpiration? Creation of the World Water and Climate Atlas was made possible by support from the Government of Japan (Official Development Assistance) and the United States Agency for International Development (USAID)

2 The IWMI Digital World Water and Climate Atlas brings together water, climate and agricultural data from sources around the world and presents it in an easy to use software tool. Planners can access this key water and climate data instantly, import their own data, or export data from the Atlas for use in other applications. Sri Lanka Localized Gridding Study An example of the Atlas s localization capability. This map of average total precipitation per year for Sri Lanka shows how the detail and precision of global data sets can be improved by incorporating local data. Rapid access to key climate variables for agriculture and water resource management. The core of the Atlas is 3 years of data from some 3, meteorology stations from around the world including data that was not previously available in the public domain. The IWMI Atlas provides users with monthly values for: total precipitation; amount of precipitation exceeded 75% of the time (P 75 ); average temperature; maximum and minimum temperatures; relative humidity; hours of sunshine; number of frost days; wind speed and Penman-Montieth reference evapotranspiration rates. High resolution data for regional and national planning. The Atlas s 1 minute arc (one-sixth of a degree) resolution the highest ever offered for a global data set of this kind makes it a valuable tool for local and national-level planning. The largest squares on the Atlas grid are only 16 km 2 at the equator. These grids can be even further refined by incorporating local data. Quick and easy data analysis. The Synthesizer software allows users to easily view, manipulate and analyze data according to their needs. For example, the software can rapidly identify locations that match specific agricultural needs. This function helps match crop varieties with locations that have certain climatic characteristics. Another function enables the user to create mathematical equations using the Atlas grids as variables. A simple example is T mean (T range x.5) = T min. Calculating reference evapotranspiration ,5 2, 1,5 1, Compatible with other data products for a clearer picture of agricultural potential. Users can combine information on elevation, land cover, soil type, population density vegetative indices, stream flow, developed water resources and other data to enable multi-parameter evaluations. Crop modeling. Planners can use the Atlas to see where specific crops can and cannot be grown and where certain varieties are most likely to be successful. It also helps identify regions which meet climate, soil and altitude requirements. Using the Atlas to show and manipulate data to calculate reference evapotranspiration.

3 Identifying the potential for rainfed agriculture The water/food security challenge for developing countries is to efficiently manage their water resources in the face of increasing water scarcity. The Atlas gives food security planners an accurate and easy-to-use overview of their country s situation. Rainfed crop potential Very high High Moderate Low Very low Rainfed agricultural potential for sub-saharan Africa. This map, generated from the Atlas, shows that the potential for rainfed production is near zero for all of Namibia and Botswana, for much of South Africa, and parts of Somalia and Kenya. IWMI estimates that by 225 cereal production will have to increase by 38% to meet world food demands. One of the most heated debates surrounding world food policy is whether this additional demand will require large investments in new irrigation systems or whether increased area and yields from rainfed agriculture can satisfy a substantial part of food demand. This issue is becoming increasing important as the competition between uses and users of water escalates in many developing countries. The Atlas helps identify areas where climatic conditions are favorable for rainfed agriculture. This picture can be refined further with the addition of data on soil type, elevation and land cover. Increasing the productivity of marginal rainfed agriculture is the key for many countries to radically improve food security and reduce rural poverty it is poor people who farm the bulk of marginal lands. Supplemental irrigation that delivers water to crops at key growth stages when rains fail is an affordable and effective solution. The Atlas helps identify where this approach will substantially improve crop yields. It can also make rapid assessments of the potential for water harvesting in a specific region or sub-region. Improving Irrigation Planning & Management 4, 3, 2, 1, Precipitation In the past, assembling the data necessary to plan an irrigation or water-related development project could take months. The Atlas can reduce this preparation time to days or even hours. For planners in developing countries, this access to accurate data, presented in a standardized format, means smoother project design and timely implementation. The Atlas is also a useful seasonal planning tool for irrigation managers enabling them to quickly evaluate crop water requirements. Annual precipitation and reference evapotranspiration rates. With this information, planners can estimate how much water is available on a monthly basis and how much water crops need.

4 Some applications using the World Water and Climate Atlas, taken from IWMI s research program. Answering the question: how much irrigation do we really need? As a first step towards determining the world s future irrigation requirements, IWMI researchers are using the Atlas to calculate the global potential for rainfed agriculture. Previous global studies relied on coarseresolution climate data. The new IWMI study combines the Atlas s high resolution data (39 times more accurate than the standard generally available 3 minute arc resolution) with a soil water storage capacity map and a dynamic water and crop model, to estimate potential for rainfed agriculture. The Atlas data sets high resolution allows global scale analysis without losing sight of regional scale implications. Potential for rainfed agriculture on a global scale Very high High Moderate Low Very low Potential for rainfed agriculture. On a global scale, 46% of the earth s surface is unsuitable for rainfed agriculture due to climatic constraints. This leaves approximately 7 billion ha with a potential for rainfed crop production, of which, 4.7 billion ha is classified as moderate to highly suitable. Researchers are currently refining this preliminary estimate taking into consideration non-climate related factors (e.g. areas not available for conversion to agriculture). Malaria risk mapping The Atlas is helping IWMI researchers to more accurately identify high-risk malaria areas. Previous risk mapping studies have used precipitation as the primary indicator of malaria risk. IWMI researchers are developing a picture of seasonal soil moisture content a more reliable malaria risk indicator using the climate data provided by the Atlas, with data from the Food and Agriculture Organization s Digital Soil Map of the World. Based on this information, it is possible to see where and when conditions are favorable for the breeding of malaria-carrying mosquitoes. IWMI`s research will look further refine these maps using satellite remote sensing tools. Testing New Methodologies IWMI scientists are developing a simple, single equation method for calculating potential evapotranspiration anywhere in the world a technique made possible with the Atlas comprehensive data set. This new method, extending the original Hargreaves approach, only requires data on maximum and minimum temperatures, provides a practical alternative to the Penman-Montieth method in situations where there is minimal or inaccurate climate data.

5 Data from the Atlas showing annual precipitation and reference evapotranspiration. This same data can be displayed by month. 5 4, 3, 2, -5 1, Precipitation , 2, -5 1, Reference Evapotranspiration Download the Atlas from The Atlas software and worldwide grids (nine regions, 12 months, 1 parameters) can be downloaded from the IWMI website or delivered on CD-ROM. A library of data products compatible with the Atlas is also available on the IWMI website.

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