AccuWeather.com

Are Record High Gulf Sea Temperatures Due to Oil?

Jun 22, 2010; 10:22 AM ET

UPDATE 7/3/10: There are several important updates and a conversation with one of the RTG-SST experts in the Comments thread.

UPDATE 6/28/10: An update from NDBC: "The data manager for the RTG-SST page said that the data from 42040 has been flagged in the analysis and was not used."

After seeing some discussion on a bulletin board about record sea-surface (water) temperatures in the Gulf, I got in contact with NOAA's National Data Buoy Center about the anomalies. What people are suggesting is that the abnormally high temperatures are being caused by the Gulf Oil Spill, but I was also worried that the oil could be gumming up the sensors. It turned out that the unusual readings could worsen the accuracy of weather forecasts this summer. Read on.

The buoy in question was #42040 and its location as compared to (today's location of) the oil spill per Google Maps is shown below:

The buoy is certainly within the oil area. It was said to have spiked to 95.9 F last week, eclipsing the previous June record of 92.4. Unfortunately the historical record for NDBC stations is generally missing between "the last week" and "2 months ago" so we can't see the data quoted on the bulletin board. Over the last several days the temperature rose to 90.5 and then the sensor went offline:

I thought this was rather curious as well, but they have an answer for that. Here's what they said:

"The buoy water temperatures in the Gulf are above normal values, But we don't believe it is related to the presence of oil. They are in line with NCEP SST anomaly analyses (see below) which are about 1 to 2 deg C higher than normal over most of the Gulf and even higher in the North Central Gulf."

"The large diurnal differences we have seen recently are a result of daytime heating of the buoy and likely do not reflect the actual water temperature during the hottest part of the day. The thermistor that reports water temperature is actually mounted on the interior of the buoy on the bottom of the hull, so it is actually measuring the temperature of the buoy hull and not the water directly. Most of the time this is not a problem, but during the summer, when sun angles are high and winds are light, reported temperatures can be much higher than the actual water temperatures."

"42040 is now a 10-meter buoy, and we believe the 10-meters are affected more by this than the standard 3-meter buoys. We have reduced the upper limits for release of water temperature for the Gulf buoys to 32.5 deg C to avoid the release of questionable water temperature data. We think the nighttime temperatures are more in line with the actual water temperatures."

I was a little disappointed to hear that there was that much inaccuracy with the placement of the sensor, but at least they're honest. (With a nod to Anthony Watts, here's hoping these are not used for climatological records). I also asked NOAA if they thought the sensors needed to be protected from the oil:

"There is currently nothing that we can do to protect the buoys from the oil slick, but we do not anticipate that the oil will affect the buoys in the path of the oil."

In fact, much of the northern Gulf and southeast Florida offshore areas are far above normal for this time of year (another station off the Florida Keys showed 95 degrees last week). Based on NDBC's assertion above, and the fact that the heat is widespread, I find it improbable that the oil is affecting the water temperature. Also, water normally changes temperature very slowly and the oil should be more reflective, not absorbing more heat.

They said that the buoy water temperatures were in line with the analysis, but further research told me that the buoy data goes into the analysis. That has me worried because as of 2007 a researcher stated that "It is the RTG-SST that is used to initialize many of the North American and global models." I asked NDBC about this but they could only confirm that RTG-SST "factors in both daytime and nighttime temperatures into the analysis." If bad data is going into that analysis that is going into the models, the models could theoretically be more inaccurate predicting this summer's weather, including tropical storms.

One "chicken-and-egg" question might be is the water making the land hotter or vice versa... it's been fairly hot all over the Gulf States this month - not including Texas there have been over 100 daily record highs reported so far in June. In the Florida Keys, it's the hottest first half of June in recorded history.

The record June high air temperature at Buoy #42040 is 89.2 and the temperature there just spiked to 88.9 earlier today. The same goes for dew points -- the record there is 82.8 and it's been in the upper 70s at the buoy recently.

All of this said however, there is little doubt that unusually warm sea-surface temperatures are present around Florida and in the Gulf, which will lead to the potential for stronger hurricanes (or more rapidly intensifying ones, especially near land), this season. AccuWeather.com has raised its prediction for storms this Atlantic Hurricane season to "18-21".

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com