Four weeks of climate data: Northern Tropics Temperature Recap

Because there is less land mass and more ocean, I split the regions other than the Northern Temperate Zone into six sections instead of twelve. As you can see, only the section including Africa and Arabia are showing significant warming. I think it makes sense for me to do some more region testing based on specific areas that are defined by climate and ecosystem, and the Sahara is certainly one of those regions.

The last two slices of the planet, the Southern tropic and Temperate Zones, will be recapped tonight and tomorrow.

Four weeks of climate data: Northern Tropics Region #6

 The last slice of the Northern Tropics is dominated by the Atlantic, with a small corner of South America in the far southwest and a larger corner of Africa is the east.

 Besides the South American coast, the region includes some Caribbean islands with steady weather stations reporting.

There is a nearly three degree centigrade difference between the highest and lowest temperatures of Winters. With a lot of the tropics the readings have been less than two degrees apart.

After 1975 everything looks to be warming, though the rate of warming is not getting greater.

Here's the Spring readings, the highs and lows less than two degrees apart. Again signs of warming, but no signs of steady increase.

Very convincing warming trend, but not speeding up and the highs and lows are barely a degree apart.

Signs of warming, some signs of increasing warming and highs and lows about a degree and a half apart.

Confidence of the region warming: 99.9%
Confidence of increasing rate: 79.8%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.48° C

We can definitely show a warming trend overall, but it is less than a half degree and the rate is getting can't be said to be increasing.


Warming regions outnumber non-warming regions 5-1, but no region shows an increasing rate and two give us at least 95% confidence of a decreasing rate. If we give each region equal weight, the average increase over the entire Northern Tropics is about a half degree Celsius in 56 years, a little less than the world average. The one region that shows nearly a degree jump is dominated by Saharan Africa, though it includes parts of Arabia and sub-Saharan Africa as well.

Tomorrow, we start looking at the tropics on the other side of the Equator.
 

Four weeks of climate data: Northern Tropics Region #5

The fifth slice of the Northern Tropics covers all of Central America, much of Mexico and the Caribbean the the northwest corner of South America. This is one time when it might have made sense to make the slices different widths to get the rest of tropical South America north of the Equator in our range, but I didn't do that. I will be looking at slices that are not quite as arbitrary in the future.

The grid points show the Pacific coast and very little to the west of it, but the Caribbean is full of inhabited islands and so we get a lot of grid points there.

Like many tropical regions, the overall change in this time period is very mild compared to the wild fluctuations seen in the polar regions. Still, the general trend is warming, as shown by the median graphed in red dots as usual.

Spring is similar to Winter.

Summer shows the upward trend in every metric. If climate change is considered bad news, the only good news here is that the median rose less than a half degree in 56 years.

Once again, the record highs and lows jump around a little while the median marches steadily upward.

Confidence of the region warming: 99.8%
Confidence of increasing rate: 65.8%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.43° C

We can definitely show a warming trend overall, but it is less than a half degree and the rate is getting can't be said to be increasing.


Later today, the last of the Northern Tropics, a corner of South America, a corner of Africa and a lot of the Atlantic.

Four weeks of climate data: Northern Tropics Region #4

Even at full magnification of this map, the fourth region of the Northern Tropics looks empty, but looking carefully at the top middle, you will see a few dots that represent the Hawai'ian Islands.

There is one other island in the part of the Pacific that has a reliable weather station, and that is the American protectorate Johnson Island.

The patterns of the four season in Hawai'i all look about the same. There was a general warming trend in the last half of the 20th Century, but things dropped off in the first decade of the 21st.

Even with the drop-off, the median in the 1999-2010 era is slightly higher that the median for 1955-1975.

The story is repeated again.

The big difference between Fall and the other season is how consistent the record high temperature has stayed.

Confidence of the region warming: 90.8%
Confidence of decreasing rate: 99.9%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.14° C

We can't definitely show a warming trend overall, but it is extremely mild and the rate is getting absolutely getting slower.

Tomorrow, it's the last two parts of the Western Hemisphere's sections of the northern tropics, the first part dominated by Central America and the second part combining a little of the Guyanas in South America with a part of West Africa.
 

Four weeks of climate data: Northern Tropics Region #3

The third slice of the Northern Tropics is the Pacific Ocean on the Asian side of the International Date line.

There are islands dotting this region, but I am not certain why the easternmost column is so well represented. There are either weather stations on a bunch of very small islands from the Philippines up to Japan or some of those stations are actually at sea.

The general Winter trend is upward, but the range of change from warmest to coldest is only about one and a half degrees C.

Spring shows a warming trend, again over a very limited range. Also, the big jump was between the 1955-1975 era to the 1975-1988. The rate here looks like it's slowing down.

Summer is very much like Spring, warming but slowing down, a very small range of temperatures.

The only point of disagreeing data in Fall is that the record high was over 20 years ago.

Confidence of the region warming: 99.9%
Confidence of decreasing rate: 97.9%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.52° C

We can definitely show a warming trend overall, but it is not particularly severe and the rate is getting slower.

Later today, the Western Hemisphere slice of the tropical Pacific, which means we are taking the temperature of Hawaii.

Four weeks of climate data: Northern Tropics Region #2

 Our next slice of the Tropics north of the Equator goes from 60 to 120 degrees East Longitude and comprises most of South Asia.

The coverage on land looks relatively complete.

The most noticeable trends for Winter are everything going up at the end of the 1955-1975 era and everything dropping at the beginning of this century. This pattern does not say global warming OR global cooling as much as a randomly fluctuating pattern, as good as no trend at all.
 

The Spring trends look more like a warming pattern, but not a severe one.  Each of our three methods of measuring stays in a band of about a half degree Celsius.

Summer shows a warming trend, but again of about a half degree.

Fall shows warming for sure, but not an increasing trend. The median went up .584° Celsius, more than some other seasons but not a huge change for that amount of time.

Confidence of the region warming: 99.9%
Confidence of decreasing rate: 65.8%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.50° C

We can definitely show a warming trend overall, but it is not particularly severe or does it show obvious sign of getting warmer faster.

Tomorrow, we look at the two slices that comprise most of the tropical Pacific.

Four weeks of climate data: Northern Tropics Region #1

After a few days of recap, we return to looking at new areas in our four weeks of climate data. By splitting the tropics into North and South, the amount of land area is reduced significantly in a slice, so we will split the region into six slices instead of twelve. Moreover, as we move south from the Northern Temperate Zone, there is a lot less land mass and a lot more water.  Our first slice has the most land mass of all the sections of the Northern Tropics, the bulk of Africa in these latitudes and the southern part of the Arabian Peninsula.
 

While there is a lot of land, the coverage by weather stations is not as consistent as we might hope. The Arabian Peninsula has nearly no coverage and there are gaps in Africa as we move away from the coast.

First things first. Damn, it's hot! Notice that 30° C is on all our scales from Winter to Fall. In the Northern Temperate Zone, averaging 15° C was unusually warm. (For Americans, 15° C is less than 60° F, 30° C is 86° F.)

Every reading takes two steps up and one step down. The difference in the median from 1955-1975 to 1999-2010 is about a degree. The record high was 2010.

Not a lot of data for climate change deniers to latch onto here.

In the Spring data, there is absolutely no good news for the deniers. Every step from left to right is a step up and the most recent steps are steeper. The median rise from the first interval to last is more than a degree. The record high was set in 2010.

If all the data looked like this, there would be no argument.

Once again, this is a pattern that argues strongly for a warming trend.

The strongest warming argument here is the median. The strongest argument against is the record high temperature is about twenty years old.

Confidence of the region warming: 99.99%
Confidence of increasing rate: 65.8%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.96° C

This region is warming, but we are not confident that the rate of increase is speeding up. The rise in the median 56 years is close enough to a full degree to be alarming.

Later today, the second slice of the Northern Tropics, which covers almost all of South Asia.