Spatiotemporal change in geographical distribution of global climate types in the context of climate warming

Abstract

After standardizing global land climate gridded data from the Climatic Research Unit TS (time-series) 3.1 dataset for the period 1901–2009, cluster analysis is used to objectively classify world climates into 14 climate types. These climate types establish a baseline classification map and the types are named according to Koppen–Geiger climate classifications. Although the cluster analysis and Koppen classification methods are very different, the distributions of climate types obtained by the two methods are similar. Moreover, the climate types we identify also coincide well with their corresponding vegetation types. Thus, cluster analysis can be used as an effective alternative to the Koppen classification method for classifying world climate types. The spatial and temporal changes in geographical distribution of global climate types were investigated in 25-year intervals, and Cohen’s kappa coefficient is used to detect agreement between the periods. Globally, although an obvious trend in increasing global temperature is found, distribution of climate types overall show no distinct changes over the periods. However, at the regional scale, spatial change in distribution of climate types is evident in South America and Africa. In South America, larger areas of the “fully humid equatorial rainforest” (Af) and “equatorial savannah with dry winter” (Aw) climate types have changed types. In Africa, changes mainly occurred in the Af, “equatorial savannah with dry summer” (As), Aw, “steppe climate” (BS), and “desert climate” (BW) climate types. Moreover, some climate types, including Af, “equatorial monsoon” (Am), BS, BW, and “tundra climate” (ET), were susceptible to temporal climate changes, especially in the period 1976–2009.