1.1 INTRODUCTION
Drought is a normal, recurring feature of climate. It occurs in virtually all climatic regimes. It is a temporary aberration, in contrast to aridity, which is a permanent feature of climate and is restricted to low rainfall areas. Sub humid, semiarid, and arid regions are especially drought prone because these regions are often characterized by highly variable inter annual precipitation.
Agriculture in these regions is frequently quite tenuous, even in normal years, but it is especially vulnerable in below-normal years. Even in more humid climatic zones, drought is often a common feature of the climate, so agriculture is one of the key sectors affected by drought. The agricultural sector would be a primary beneficiary …show more content…
Due to the growth of population and expansion of agricultural, energy and industrial sectors, the demand for water has increased many folds and even water scarcity has been occurring almost every year in many parts of the world. 1.2 NEED FOR DROUGHT RESEARCH
Drought can be defined as a significant reduction in water resources during a long period of time in a large spatial area which leads to negative consequences.
These episodes have traditionally been regarded as an agricultural problem and thus the economic impacts have been considered limited to the rural environments.
However, current water uses cover a broader scope of economic activity and water deficits generate impacts in a greater number of sectors. The specific objective of this study is to estimate the direct economic impacts of a drought episode in Greece and specifically in the areas with a high cereal production.
The motivation for current study is due to global drought scenarios during recent years and the results will be discussed in what follows.
*Resource: Médecins Sans …show more content…
Operational definitions on the other hand, help identify the drought's beginning, end, and degree of severity of drought periods.
Some of the commonly used definitions are:
The World Meteorological Organization (WMO, 1986) defines drought means a sustained, extended deficiency in precipitation.
The UN Convention to Combat Drought and Desertification (UN Secretariat General, 1994) defines drought means the naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resource production systems.
The Food and Agriculture Organization (FAO, 1983) of the United Nations defines a drought hazard as the percentage of years when crops fail from the lack of moisture.
The encyclopedia of climate and weather (Schneider, 1996) defines a drought as an extended period – a season, a year, or several years – of deficient rainfall relative to the statistical multi-year mean for a region.
Gumbel (1963) defined a drought as the smallest annual value of daily stream