Search results
Results From The WOW.Com Content Network
Aridity increased, with the Ghaggar-Hakra River retracting its reach towards the foothills of the Himalayas, [64] [67] [68] leading to erratic and less-extensive floods, which made inundation agriculture less sustainable. Aridification reduced the water supply enough to cause the civilisation's demise, and to scatter its population eastward.
An aridity index (AI) is a numerical indicator of the degree of dryness of the climate at a given location. The American Meteorological Society defined it in meteorology and climatology, as "the degree to which a climate lacks effective, life-promoting moisture".
In agriculture, this is called a crop coefficient. The difference between potential evapotranspiration and actual precipitation is used in irrigation scheduling. Average annual potential evapotranspiration is often compared to average annual precipitation, the symbol for which is P. The ratio of the two, P/PET, is the aridity index.
For example, temperature increase by 1.5–2.1 percent across the Nile Basin over the next 30–40 years could change the region from semi-arid to arid, significantly reducing the land usable for agriculture. In addition, changes in land use can increase demands on soil water and thereby increase aridity. [6]
Aridification is the process of a region becoming increasingly arid, or dry.It refers to long term change, [1] rather than seasonal variation. It is often measured as the reduction of average soil moisture content.
Desertification is a gradual process of increased soil aridity.Desertification has been defined in the text of the United Nations Convention to Combat Desertification (UNCCD) as "land degradation in arid, semi-arid and dry sub-humid regions resulting from various factors, including climatic variations and human activities."
The United States Department of Agriculture's Healthy Eating Index reflects this need for better-quality American diets. The most recent index found that Americans (above the age of 2) scored an ...
Thornthwaite developed four indices: the Moisture Index (Im), the aridity and humidity indexes (Ia/Ih), the Thermal Efficiency Index (TE) and the Summer Concentration of Thermal Efficiency (SCTE). Each of the four climatic types can be described by an English alphabet letter and are arranged exactly by the order shown previously. [5]