Drought and Heatwave Flashcards
Heatwave definition
A period of high temperatures relative to typical seasonal conditions for a location
Duration in the UK
> _ 3 days
Anticyclones
Large scale high pressure systems, light winds, decending air inhibits cloud formation
Humans require what core temp
~90 W
At low temperatures
radiation, conduction, convection and perspiration are effective
At high temperatures
perspiration is effective
Perspiration becomes ineffective at
high levels of humidity
What inhibits convective mixing and trap emissions
Temperature inversions
What enhances ozone production
Clear skies and strong radiation
What happened in England and Wales during 2003?
21 - 38% of total excess deaths
What were the excess deaths due to in 2003
elevated ambient ozone and PM 10 concentrations
Soil Moisture deficit
increases the frequency, duration and severity of hot spells
Example of a location experiencing soil moisture limited areas
Southern Europe
Wetter regions
experience a weaker relationship of frequency, duration and severity of hot spells
Weather fatalities in the US 2021 main cause
Heat
Which cause of weather fatalities has the highest 30 yr average
Heat
How are heatwaves measured ( USA)
Heat Index Chart
What is the NHS Heatwave Plan for England
vulnerable groups are to include elderly people ( >65) and people with pre-existing medical conditions
How are urban residents are at higher risk?
Urban Heat Island effect and increased risk of air polution
Mitigation strategies in the UK
heatwave alert levels and Gov related release of mitigation acts
What is the long term mitigation stragety
Urban planning via afforestation, cool infrastructure
How do heatwaves have gloabl affects
1) arctic sea ice loss
2)decrease albedo effect
3)atmospheric warming
1)Increase wildfire activity
2) vegetation loss and thawing permafrost
3) Loss of CO2
4) atmospheric warming
Drought definition by the IPCC
moisture deficit in relation to the average water availabitlty at a given location and season
Meteorological drought
Period of lower rainfall
Duration of drought
Days to years ( location dependent)
Occurences
Typically northen African regions and subtropical regions
Environmental impacts
Loss of moisture from a system
List of the types of Loss of moisture from a system
Wetland
drying of seasonal water bodies
reduction of vegetation cover
loss of wildlife habitat soil erosion
wildfires
wildlife migration
disease
Socio-economic impacts
Cash crop failure
Loss of lifestock
What is the Sahel drought?
Semi arid
Dry and wet seasons
How much does it rain in Sahel
(100-800mm/yr)
What is rainfall driven by
Tropical convection,west african monsoon , el nino
What happened during the 1960’s-1990’s
Causes of Droughts
Regional and remote forcing
Regional forcing examples
Overgrazing,deforestation for agriculture
Increased surface albedo less solar energy absorbed
reduced moisture supply to atmosphere, less rainfall
Unfavorable conditions for vegetation growth
Remote forcing examples
Changes in sea surface temps
Atlantic multidecadal Oscillation
Dust feedbacks
Aerosol -related forcing
Ethiopia example
droughts are related to existing vulnerability
Exacerbated by…
- rural destitution
-environmental degradation
-war and conflicts
What happened during 1999-2000 crisis
10 mill in need of food assistence
Migration and Adaptation strategies
Landscape management
