Presentation on theme: "Hydrosphere Partitioning… Total = 1.36 x 10 9 km 3 water."— Presentation transcript:
Hydrosphere Partitioning… Total = 1.36 x 10 9 km 3 water
Earth’s water balance (Fluxes per year) Ocean Volume = 1.4x 10 9 km 3 Oceanic Evaporation Rate = 3.2x10 5 km 3 /yr Groundwater Volume = 8.4x10 6 km 3 (o.6%) River+Lake Volume = 2x10 5 km 3 (o.014%) Atmosphere Volume = 1.3x10 4 km 3 Runoff Rate = 3.6x10 4 km 3 /yr
89% of rain falls over oceans Land receives ~11% of ocean’s evaporation (36,000 km 3 ) Twice as much water evaporates (&transpires) from land as runs off it e.g. rain on land falls three times on average before it gets back to sea
Residence times in ground, rivers, & atmosphere Residence time defined as the (Volume of ‘Reservoir’)/(Rate of flow through Reservoir) For groundwater = 8.2x10 6 km 3 / 3.74x10 4 km 3 /yr = 224 years For rivers & lakes = 2x10 5 km 3 / 3.74x10 4 km 3 /yr = 5.3 years For atmosphere = 1.3x10 4 km 3 / 3.8x10 5 km 3 /yr = 12 days
Why do raindrops not grow to be huge? They self-destruct once they grow too big!
Atmosphere temperature & condensation Adiabatic effects on rising and sinking air: Air cools when it rises & is decompressed. Air warms up when it descends & is compressed. (reason why a bike pump gets hot when pumped)
Atmosphere temperature & condensation
A mechanism to lift air/trigger condensation
Another way to lift air…(warm front) Moderate Precipitation ~200 km 1/200
Different Variation (cold front)… ~100 km 1/100
Lifting-precipitation reason for climate belts
Coriolis Force key influence on weather fronts & storms (Cyclonic effects)
Cyclonic Effects (Coriolis Revisited)
Life cycle of a thunderstorm Condensation (rain) releases heat, fuels ascent Unstable warm air rises Downdrafts cut off fuel (warm air) & storm dies
A hurricane can circumvent this limit…
Hurricane wind & rain structure
Regions where hurricanes form… Warm water = hurricance fuel.
Hurricane paths near US
Two Cyclones: What difference & why?
New Orleans Experience Hurricane surge (wind-driven waves was up to 28ft above sealevel — new record for US) Why were Mississippi & Alabama also severely affected, but not Texas? Path of Katrina’s eye N.O.
New Orleans— Flooding from Hurricane Surge & Rain Path of Katrina’s eye
New Orleans Experience — Flooding (Marshak Fig )
Estimating Threat from Flooding (Recurrence Interval)