Lecture 9: Drought

• Drought- normally associated with an unusual shortfall of precipitation.
• Flash Drought- moving from drought-free conditions to extreme drought within a matter of weeks.
• Semi-arid regions: low mean rainfall, high variability of total rainfall. lack of reliable rainfall.
• Meteorological Drought: rainfall defecit.
• Hydrological Drought: stream flow deficit. sufficient reduction of stream discharge or groundwater levels.
• Agriculture Drought: soil moisture deficit. soil moisture insufficient to maintain average crop yield.
• Famine Drought: food deficit. extreme form of agriculture drought.
• Physical Causes: associated with anomalies in global atmospheric circulation. large connections between atmosphere and oceans.
• Drought most likely triggered by: relatively cold sea surface temperature anomalies.
• Human Factors: desertification, overcultivation, war, deforestation.
• Protection: involves environmental control, like cloud seeding. could also develop new water sources. large dams and water transfers.
• Mitigation: form of crisis management, distribution of disaster aid and food aid.
• Adaptation: community preparedness, predictions, forecasts, warnings, land use planning.