Temporal-spatial evolution patterns of the annual precipitation considering the climate change conditions in the Sanjiang Plain

The wavelet theory, Mann-Kendall trend test and ArcGIS spatial analysis theory were used to analyze annual precipitation and mean temperature data that were collected at seven national weather stations in the Sanjiang Plain from 1956 to 2013 to identify the temporal-spatial patterns of annual precipitation changes caused by climate change conditions. The results showed that the climate in the Sanjiang Plain experienced a significant warming trend over the past 50 years, with the temperature increasing by 1.35 °C since the 1960s. Additionally, the precipitation also exhibited certain trend characteristics, which revealed a larger difference in different areas. The annual precipitation exhibited 23-year and 12-year periodic variation characteristics, and the period with above-average annual precipitation levels is expected to continue after 2013. The spatial distributions of the mean annual precipitation for different years were different, whereas the spatial distribution of the multi-year mean precipitation was relatively uniform. The annual variation amplitude of the annual precipitation in the central area was larger than that in the south. The overall inter-annual fluctuation of the annual precipitation was relatively small with a mostly normal distribution. The results can provide guidance for scientific investigations and the reasonable use of rainfall resources in the Sanjiang Plain.