Valley Climates Flashcards
WHAT IS A MICROCLIMATE?
Climate of a small area
WHICH SLOPE DIRECTION IS WARMER?
North facing slopes
WHAT ARE ANABATIC WINDS?
- In the day
- in the morning air above the valley slope heats up
- Warm air rises towards crest-causing up slope winds
- later air from the valley becomes less dense
- air moves from high pressure at the lower end to low pressure at the top of valley
- rising air cools and sometimes form clouds
WHAT IS A KATABATIC WIND?
- in the night
- air on high slope sides cools+denser and flows down valleys sides to form a downslope wind
- later air mass in the upper part of the valley cools-become denser-flows down valley
- cause down valley wind
- if flow isn’t fast-frost/fog may develop(in hollows)
WHAT ARE FROST POCKETS?
When frost forms on valley floor where cold air collects
Cold air moves down slope-collects in lowest part of valley-water vapour condenses into frost
HOW DO LOCAL CLIMATES IMPACT HUMAN ACTIVITIES?
- people prefer warmer north facing slopes
- settlements more developed mid slope
- narrow valleys-pollution/smog trapped by inversion layer
WHAT ARE THE CHARACTERISTICS OF A URBAN CLIMATE?
- More condensation/precipitation (pollution condensation surface)
- high temp(artificial surfaces)
- lower wind speed(buildings shelter)
- lower relative humidity(fewer water bodies/vegetation)
WHAT DOES THE TEMP DIFFERENCE BETWEEN URBAN AND RURAL CLIMATES DEPEND ON?
- Relief/altitude
- distance from water sources
- % of open space
- # /type of industry
WHAT IS A URBAN HEAT ISLAND?
Warmth of atmosphere in cities compared to non-urbanised
WHAT CAUSES HEAT ISLANDS?
- Traffic pollution
- high concentration of people
- rain removed quickly-less heat to evaporate water
- warm CBD air rises
- dark surfaces store heat
WHAT ARE THE EFFECTS OF HEAT ISLANDS?
- smog
- heat stress
- disease spreading weather
- +levels of ozone
- increased cost of water+energy
WHAT IS A POLLUTION DOME?
Mass of polluted air in & above cities
-air cant rise because of inversion layer
WHAT HAPPENS TO A POLLUTION DOME IN CALM, STABLE AIR?
- Temp decreases with altitude
- formation of precipitation inhibited- higher temp in inversion layer
WHAT HAPPENS TO A POLLUTION DOME WITH WIND?
- Pollution carried downwind forming pollution plume
- particulates serve as nuclei for condensation-precipitation enhanced downwind of urban area-increase particulates
WHAT ARE THE EFFECTS OF A POLLUTION DOME?
- Lead poisoning
- respiratory discomfort
- increased cloud cover
- acid rain
- smog(higher temp)
