Spatial and Temporal Analysis of Annual Rainfall Variations in Turkey

Abstract

This paper presents the spatial and temporal characteristics of Turkey's annual rainfall data in the context of climatic variability. Basic data consists of the monthly rainfall totals from 91 stations with a record length ranging from 54 to 64 years, during the period 1930–1993. Basic elements of the rainfall climatology have been examined and then normalized rainfall anomaly series have been analysed for long‐term trend and fluctuation and changes in runs of dry and wet years, for all of Turkey, rainfall regime regions, and individual stations. All regional mean rainfall anomalies have tended to vary in a statistically coherent manner over the rainfall regions. Area‐averaged annual rainfall series have decreased slightly over all of Turkey and apparently over the Black Sea and Mediterrane an rainfall regions. Results of the Mann–Kendall test, however, have indicated that none of the decreasing trends in the area‐averaged rainfall series were significant. Annual series of 17 stations showed a significant trend in the mean and a majority of these trends are downward. Many of the stations have experienced marked low‐frequency fluctuations in the annual rainfall. The concurrences of the dry conditions between the rainfall regions and the rest of Turkey have appeared generally during the early 1930s, the late 1950s, the early 1970s, around the 1980s and the early 1990s and of wet conditions generally during the period 1935–1945, around the 1960s and the late 1970s. The change points for the beginning of drier than normal conditions occurred in the early 1970s and early 1980s over most of the country. Annual rainfall variations over the rainfall regions except the Black Sea region were related closely to those of the rest of Turkey.

Impact of Climate Change on Irrigation Demand and Crop Growth in a Mediterranean Environment of Turkey

“…Precipitation is projected to decrease by about 163, 163 and 105 mm over the period of 1990 to 2100 under the A2 scenario of the CGCM2, ECHAM4 and MRI models, respectively. Decreasing rainfall trends in Turkey have already been observed during the 20 th century [45]. …”

Influence of geopotential heights, cyclone frequency and southern oscillation on rainfall variations in Turkey

“…Results from the Mann-Kendall test for 91 stations and visual interpretations on the time-series plots (not presented) are summarized as follows. (i) Annual rainfall series of many stations show a low-frequency fluctuation with a decreasing mean over the study period, and are generally characterized by a longer run of the dry (relatively drier than long-term average) conditions from early 1970s (Tü rkeş, 1996b). Observed downward trends are significant at the 15 stations.…”

“…Eight stations were added to these 91 stations solely for the study of rainfall climatology of Turkey, in which three of those have relatively shorter records, and others show some inhomogeneity. The rainfall data was broadly discussed in an earlier paper (Tü rkeş, 1996b). The locations of the 99 stations with numbers used in this paper are shown in Figure 1.…”

Türki̇ye De Lodos Un Si̇nopti̇k Kli̇matoloji̇si̇ (Samsun İli̇ Örneği̇)

“…Flocas et al, (2010: 5244), 20° ile 38° doğu boylamları arasında uzanan Doğu Akdeniz havzasını, Subtropikal ve Orta enlemlerin etkisi yanında karışık topoğrafya sahip olduğunu ve lokasyonun siklon davranışı açısından ilginç bir alana karşılık geldiğini belirtmektedir. Türkeş (1996Türkeş ( : 1058 ise, üç tarafı denizlerle çevrili olan Türkiye'nin aynı zamanda batıdan doğuya doğru hareket eden cephesel siklonların doğal geçiş alanı konumunda bulunduğuna vurgu yapmaktadır.…”