Earth Average Temperature

[Bill Johnson]

Does anyone have the details on how the earth's yearly average temp is derived?

I assume there are thermometers all over the place, but how many are there, how are they coordinated, how frequently are temps taken, etc.

 

 

[studiot]

1 hour ago, Bill Johnson said:

Does anyone have the details on how the earth's yearly average temp is derived?

I assume there are thermometers all over the place, but how many are there, how are they coordinated, how frequently are temps taken, etc.

 

 

Yes indeed at one time there were lots of thermometers around.

They were unevenly distributed over the globe, depending upon the resources of their nations in charge of their location.
Also the readings were of uneven quality and some readings were more frequent than others.
Readings were also taken at sea and more recently in the air by aircraft and ballons, manned and unmanned.

 

Today we have the benefit of continuous near blanket monitoring by weather satellites using remote thermal imaging techniques.

 

Both the average and local temperatures are known to affect various marker such as plant growth and pollen production, ice thicknesses and so on.

Records of these from ice cores and fossils are used by paleoclimatologists to establish past temperatures.

 

Does this help ?

[Ken Fabian]

1 hour ago, Bill Johnson said:

Does anyone have the details on how the earth's yearly average temp is derived?

I assume there are thermometers all over the place, but how many are there, how are they coordinated, how frequently are temps taken, etc.

 

 

Weather station data is used for most of the global temperature datasets and most of that is records of daily maximums and minimums. Looking at such records was one of the ways to determine whether we have been experiencing climate change and the reason most datasets start from the late 1800's. Ships also provide temperature data used for temperatures over oceans.

Homogenization is done to make data in a variety of formats compatible with each other and to remove sources of bias such as different and changing weather station technology, shifting of sites and my understanding is some datatsets preference nearby rural stations over urban ones where urban heat island appear to make a bias. Comparing nearby stations that experience similar weather and temperatures is one way of identifying problem stations.

Usually they divide the world up into smaller areas and average the stations within each before going on to make a global average from those - this is to compensate for some regions having a lot of weather stations and other having few; simply averaging all the weather stations together would distort the results by making it an average of the places with the most stations rather than truly global.

The addition of satellite data provides consilience - ie shows much the same result by other means and affirms them, but it is even more reliant on processing the data, by means that are opaque to the non-expert.

[studiot]

12 hours ago, Ken Fabian said:

Weather station data is used for most of the global temperature datasets and most of that is records of daily maximums and minimums. Looking at such records was one of the ways to determine whether we have been experiencing climate change and the reason most datasets start from the late 1800's. Ships also provide temperature data used for temperatures over oceans.

Homogenization is done to make data in a variety of formats compatible with each other and to remove sources of bias such as different and changing weather station technology, shifting of sites and my understanding is some datatsets preference nearby rural stations over urban ones where urban heat island appear to make a bias. Comparing nearby stations that experience similar weather and temperatures is one way of identifying problem stations.

Usually they divide the world up into smaller areas and average the stations within each before going on to make a global average from those - this is to compensate for some regions having a lot of weather stations and other having few; simply averaging all the weather stations together would distort the results by making it an average of the places with the most stations rather than truly global.

The addition of satellite data provides consilience - ie shows much the same result by other means and affirms them, but it is even more reliant on processing the data, by means that are opaque to the non-expert.

Good points, Ken. +1

But I think you should go back a little further than you suggest for the history.

 

The groundwork was laid in the 1600s by Hooke and Newton and continued in the 1700s by the Europeans, starting with Farenheit. This lead onto Kelvin's Absolute temperature in the early 1800s.

So by the time of the French- Spanish geodetic expedition to Peru temperature measurement was routine. They made the first systematically recorded temperature observations in South America.

 

Hooke produced the first standard rain guages, wind guages, temperature gauges  etc necessary for properly established scientific recording.
Here is his scheme.

[Chhavi421]

On 9/2/2023 at 2:31 AM, Bill Johnson said:

Does anyone have the details on how the earth's yearly average temp is derived?

Yes, there is plenty of information available online about how the Earth's average yearly temperature is derived. The main source of this data is NASA's Goddard Institute for Space Studies (GISS), which compiles years of global air and sea surface temperature data to produce maps and estimates of global temperature changes. Additionally, scientists from the National Oceanic and Atmospheric Administration (NOAA) use a combination of data from satellites, weather stations, ships, buoys, and weather balloons to measure sea surface temperatures and other indicators of climate change. You can also find a variety of articles and research papers on the subject if you do some research.

[amaila3]

Certainly! Earth's yearly average temperature is determined through a global network of weather stations, satellites, and ocean buoys. Thousands of thermometers worldwide record temperatures daily, typically at fixed hours (e.g., every hour). These data points are collected, quality-checked, and averaged to calculate daily averages for various locations. These daily averages are then used to compute monthly and annual averages. International organizations like the World Meteorological Organization oversee data coordination and ensure uniform standards. Satellite measurements provide valuable information for remote areas. Ultimately, this comprehensive network allows scientists to calculate the Earth's yearly average temperature, providing vital insights into climate trends.