Saturday, August 20, 2011

New Jersey combined temperatures

Crossing from Delaware into New Jersey as I come toward the end of the data acquisition part of the project I started last year looking at state temperatures over the past one hundred and fifteen years, I find that New Jersey has a dozen USHCN stations.

Location of the USHCN stations in New Jersey (CDIAC ).

According to the list, the only GISS station in the state is in Atlantic City. There have been 3 stations there, one that ran from 1895 to 2008, down at the Marina. This clearly shows the drop in temperature in the 1948 – 1965 period that I have been mentioning in the last few posts on the subject.

Longer term temperature profile reported for the GISS station in Atlantic City (GISS ).

However, as has become evident in many states that I have reviewed, the one that is being used by GISS has a much more recent history, only having been in operation since 1951.

That record also clearly shows the temperature drop, though with the start in 1951, it is not as clear that this is an anomaly from the overall rising trend.

Reported temperatures for the GISS station currently being used in Atlantic City (GISS ).

Given the steady rise in temperature of the station at the Marina, I was curious to see how far from the sea the new station is. It turns out to be at the airport, which is 9 miles from the sea, and 23 m above sea level.

Location for the current GISS station in Atlantic City, New Jersey.(Google Earth)

And then as I start to import the data for the USHCN stations, I find that the first one is still at the Atlantic City Marina:

Location of the USHCN station in Atlantic City, at the Marina (Google Earth)

New Jersey is 150 miles long and 70 miles wide, running from 73.9 deg W to 75.58 deg W, and 38.9 deg N to 41.3 deg W. The mean latitude is 40.1 deg , that if the USHCN stations is 40.3 deg N, and the GISS station is at 39.45 deg N. The elevation of the state runs from sea level to 549 m, with a mean elevation of 76.2 m. The mean USHCN station is at 53.9 m, while the GISS station is at 23 m.

Because of the short interval for which information from the current GISS station has been presented, the difference between it and the USHCN average is relatively short.

Difference between the data presented for the GISS station in New Jersey and the average of the USHCN stations

For the state itself, turning to the Time of Observation corrected (TOBS) raw data, and seeing how the temperature in the state has changed over the years:

Change in the TOBS temperatures, on average, for the USHCN stations in New Jersey.

It can be seen that there has been, with the exception of the time from about 1950 to 1965, a steady increase in temperature. As I had noted in an earlier post on Rhode Island the sea surface temperatures (SST) have risen by about 1.8 deg F per century. This is relatively close to the value shown in the above graph. (Note that the homogenized data plot shows a temperature rise of 2.45 deg F per century.)

Turning to the geographical factors, starting with latitude:

Effect of station latitude on temperature in New Jersey

Remember from previous observation that longitude is really a proxy in many cases for changes in elevation, and New Jersey is, in the main, relatively flat:

Effect of station longitude on temperature in New Jersey

There is really no significant effect of longitude, whereas when one looks at elevation:

Effect of station elevation on temperature in New Jersey

It is clear that the broadly consistent finding from other states on the role of elevation is valid also here, even with relatively smaller elevation changes.

When looking for populations, Charlotteburg has only one farm by it at the moment, but there are two sets of sub-divisions being developed in the neighborhood, which may have a significant impact on recorded temperatures in the future, though the reservoir may have a stabilizing effect.

Location of the USHCN station at Charlotteburg, NJ (Google Earth)

Indian Mills also did not come up with a citi-data site, so a check with Google Earth showed that it was close to Medford Lakes and that the station was surrounded by houses (with large lots). So I used the Medford Lakes population. Moorestown is on the edge of Philadelphia, but has a separate population,

Looking therefore at the effect of population, considering the average of the last 5 years temperatures against the local population:

Effect of local population on TOBS temperature for the USHCN stations in New Jersey.

Interestingly the homogenization of the data for the USHCN reported temperatures also creates a higher R^2 for this state.

Effect of local population on homogenized temperature for the USHCN stations in New Jersey.

Which suggests there might be some difference between the two sets of data, as there would appear to be. The recent drop is a little less than common to many earlier states.