LACK of vegetation may be the reason northern Oklahoma hotter than elsewhere

Tuesday, August 7th 2001, 12:00 am
By: News On 6

CHEROKEE, Okla. (AP) _ A northern Oklahoma community's status as an agricultural town may be why it saw daytime temperatures usually found in the southwestern part of the state.

For nearly half of July, the hottest temperature in the state was recorded in Cherokee. The Alfalfa County town had an average daily high temperature of 105 degrees. Highs of 109 degrees were reported on July 23 and 30 and the mercury reached 110 degrees on July 22.

A climate expert believes the region's wheat harvest has something to do with the extreme heat.

``I would suspect that that kind of heat anomaly results from the fact that all the wheat has been harvested,'' said Renee McPherson, associate director of the state Climatological Survey.

The harvest leaves bare soil, and when bare soil absorbs the sunlight, it is converted more directly to heat than that same amount of sunlight over vegetation, McPherson said.

She noted that vegetation puts water vapor into the air and that dry air heats faster than moist air. Combined, the dry air and bare soil boost temperatures, McPherson said.

North-central Oklahoma has the state's largest percentage of wheat fields and, therefore, a larger percentage of bare land in July, she said.

Alva, in northwestern Oklahoma, twice had the state's hottest temperature in July, peaking at 109 degrees on July 11. Hooker, in the Panhandle, also was the state's hot spot early in the month, topping out at 107 degrees July 9.

McPherson said Cherokee may be hotter than areas farther south because of the increased presence of summer crops such as cotton or range land in southern Oklahoma to help offset the July heat's impact.

Mark Hodges, Oklahoma Wheat Commission executive director, said he couldn't state specifically why Cherokee was the state's hot spot several days last month, but he added that ``crop production does affect weather.''

Much of Cherokee's region isn't suited to a summer crop such as soybeans because that crop needs darker, deep soils instead of the thinner, red soils found in areas like Cherokee and Alva.

Last year, north-central Oklahoma was again hotter than much of the state from July through October.

In September, the average temperature in Cherokee was 92 degrees, compared with 90 degrees for the rest of the state.