MESONET TICKER ... MESONET TICKER ... MESONET TICKER ... MESONET TICKER ... September 1, 2005 September 1, 2005 September 1, 2005 September 1, 2005
Fingerprints of Rain Show up in Atmosphere
The first two Tickers of the week described the prolonged dryness in southeastern Oklahoma, and how this contributes to fire danger. Well, the situation hasn't changed, as this map of rainfall in the last 90 days shows:
http://ticker.mesonet.org/archive/20050901/last90daystot.png
We are all very familiar with the atmosphere's impact on surface conditions. But this communication of energy and water molecules is a two-way street. Through evaporation and plant transpiration, collectively known as evapoptranspiration (ET), the surface transfers water back to the atmosphere.
Of course, the amount of available soil water helps govern the rate at which water is surrendered. And we can see the profound difference that soil water content plays on calm, sunny days like yesterday. The clear, high, summer sun provides plenty of energy to prod ET processes along, and, when the atmosphere relaxes its large-scale patterns, local impacts become much more obvious.
What we are left with is this afternoon dew point map:
http://ticker.mesonet.org/archive/20050901/regionaldewpts.png
Notice how, in the drought-plagued areas of the southeast, dew points were relatively low, but for the rest of the state, they shot up to near 70! The demand for ET was about the same, but the dry southeast was unable to supply the atmosphere with water at nearly the same rate as the rest of the state.
The difference between the two regimes - in terms of potential energy - cannot be understated. The 15-degree difference in dewpoint represents tons and tons of water vapor in the over patches of earth as small as a baseball field.
Better understanding these and related land-atmosphere processes are one key to more accurate conceptual models of the atmosphere, which is one key to more accurate forecast models, which is one key to more accurate forecasts.
==================================================
The OCS/Mesonet Ticker
https://ticker.mesonet.org/
To subscribe or unsubscribe from the Ticker
or for questions about the Ticker or its content
Phone or Email the Ticker Manager at OCS
Phone: 405-325-2253 Email: ticker@mesonet.org
---------------------------------------------------
-C- Copyright 2024 Oklahoma Climatological Survey
===================================================
|