Thursday, July 5, 2012

7/5 - 11:30pm - Louisville Urban Heat Island This Week

It goes without saying that it's been incredibly hot this week in Louisville. This is all thanks to an expansive ridge of high pressure over the center of the country. High temperatures have been record-breaking every day this week except Tuesday when the high at the airport was below 100. This stretch of triple digit temperatures dates back to June 28th and there appear to be at least two more days of 100-plus weather ahead. The urban heat island effect, which causes temperatures in concrete and asphalt-filled urban areas to be higher than more vegetated suburban and rural areas, has been pretty apparent with the extreme heat. Temperature readings at Louisville International Airport have been consistently higher than other observation sites within the city and this is easy to see when comparing the high and low temperatures for each day this week with surrounding stations. Below you'll find the high and low temperatures for each day of the week so far at Louisville International Airport (KSDF), a personal weather station in Shively (West Louisville), Bowman Field, and a personal weather station in Fisherville (East Louisville):

Thursday July 5th

Louisville Airport 104/78 | Shively 100/72 | Bowman 102/78 | Fisherville 98/72

Wednesday July 4th

Louisville Airport 102/76 | Shively 101/76 | Bowman 99/76 | Fisherville 97/69

Tuesday July 3rd

Louisville Airport 97/73 | Shively 97/73 | Bowman 96/72 | Fisherville 93/67

Monday July 2nd

Louisville Airport 100/73 | Shively 99/73 | Bowman 99/71 | Fisherville 96/67

Sunday July 1st

Louisville Airport 103/74 | Shively 102/75 | Bowman 101/72 | Fisherville 99/70

I've sorted the data above from most urban (the airport) to least urban (Fisherville), so it's not hard to put together that temperatures generally decrease as you get further away from the dense center of Louisville. The Fisherville observation station is located in a valley in the eastern portion of the county, so the low temperatures each morning are a bit cooler than they would be otherwise due to cool air settling into the valley at night. High temperatures at this station shouldn't be affected by the valley and this checks out because I've been keeping an eye on the observations in Shelbyville, which is down the street from Fisherville, so to say. This warmth due to the urban heat island near the airport is significant because this is where the official temperatures for the city are taken. If it's 100 degrees at the airport, the rest of the city is probably seeing temperatures a degree or two cooler.

This difference in temperature between the airport and the rest of the city was the focus of some research I published in April for a class at Mississippi State University. I used quite a bit of historical data to figure out how much the urban heat island "distorts" the temperatures at the airport. Go check out my research by clicking this link to a blog post I penned earlier this year.


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