The raw data, collected from hundreds
of weather stations around the world and analysed by his unit, has been used for years to bolster efforts by the United Nation's Intergovernmental Panel on Climate Change to press governments to cut carbon dioxide emissions.
Whereas meteorological variables like temperature, humidity, winds and precipitation were routinely measured
at weather stations around the world, there were little or no observations of land surface states like soil temperature, moisture, and snow mass, or important terms of surface energy and water budgets such as shortwave and longwave radiation, evaporation or sensible heat fluxes.
Dropped stations introduce warming bias «Two American researchers allege that U.S. government scientists have skewed global temperature trends by ignoring readings from thousands of
local weather stations around the world, particularly those in colder altitudes and more northerly latitudes, such as Canada.»
In the paper1, the authors used data
from weather stations around the world; those in China «were selected on the basis of station history: we chose those with few, if any, changes in instrumentation, location or observation times», they wrote.
Last week, the UK's Met Office attempted to quell the growing anger at its lack of openness by «releasing» data from 1700
weather stations around the world.
The data were gathered from
weather stations around the world and then adjusted to take account of variables in the way they were collected.
Besides these thousands of thermometer readings from
weather stations around the world, there are many other clear indicators of global warming such as rising ocean temperatures, sea level, and atmospheric humidity, and declining snow cover, glacier mass, and sea ice.
When scientists in the 1960s - 70s compiled data to build their global average temperature series they used state averages of monthly mean temperatures from
weather stations around the world.
The German scientist then randomly selected 120
weather stations around the world and manually compared the archived data to GISS» 2012 temperature records.