Global Record From 1850
The period for which reasonably reliable instrumental records of near-surface temperature exist with quasi-global coverage is generally considered to begin around 1850. Earlier records exist, but with sparser coverage and less standardized instrumentation.
The temperature data for the record come from measurements from land stations and ships. On land, temperature sensors are kept in a Stevenson screen or a maximum minimum temperature system (MMTS). The sea record consists of surface ships taking sea temperature measurements from engine inlets or buckets. The land and marine records can be compared. Land and sea measurement and instrument calibration is the responsibility of national meteorological services. Standardization of methods is organized through the World Meteorological Organization and its predecessor, the International Meteorological Organization.
Currently, most meteorological observations are taken for use in weather forecasts. Centers such as ECMWF show instantaneous map of their coverage; or the Hadley Centre show the coverage for the average of the year 2000. Coverage for earlier in the 20th and 19th centuries would be significantly less. While temperature changes vary both in size and direction from one location to another, the numbers from different locations are combined to produce an estimate of a global average change.
Read more about this topic: Instrumental Temperature Record
Famous quotes containing the words global and/or record:
“However global I strove to become in my thinking over the past twenty years, my sons kept me rooted to an utterly pedestrian view, intimately involved with the most inspiring and fractious passages in human development. However unconsciously by now, motherhood informs every thought I have, influencing everything I do. More than any other part of my life, being a mother taught me what it means to be human.”
—Mary Kay Blakely (20th century)
“Death is another milestone on their way.
With laughter on their lips and with winds blowing round them
They record simply
How this one excelled all others in making driving belts.”
—Stephen Spender (1909–1995)