3. Empirical Study of the Climate
3.1. I troductio To both u dersta d the prese t climate a d to predict future climate cha ge, it is ecessary to have both theory (chapters 1 a d 2) a d empirical observatio . A y study of climate cha ge i volves the co structio (or reco structio ) of time series of climate data. How these climate data vary across time provides a measure (either qua titative or qualitative) of climate cha ge. Types of climate data i clude temperature, precipitatio (rai fall), wi d, humidity, evapotra spiratio , pressure a d solar irradia ce. Duri g the most rece t history, scie tists have bee able to co struct climate time series from empirically observed i strume tal data. Although the lo gest of these is a temperature record from ce tral E gla d begi i g i the 17th ce tury (Ma ley, 1974), the period traditio ally associated with i strume tal records exte ds back o [...]