Precipitation characteristics and changes

Precipitation over the Arctic region plays a significant role in the water and energy cycle that sustains the Arctic's unique ecosystem. Although a cold climate with strong seasonality in temperature and moisture predominates, there is large spatial variation due to the heterogeneity of the landscape and atmospheric processes that control local weather and climate. Long-term historical synoptic records exist for some regions providing very valuable information on how precipitation has been changing, yet there are many challenges to overcome. Inconsistency in instrumentation and measurement techniques, undercatch due to weather conditions and precipitation types, uneven spatial and temporal distribution of station locations, and the reliability of remote sensing products all have to be considered. Research on Arctic precipitation is mostly focused on a specific continent or geographical or political region using very diverse perspectives and approaches. Here we draw from many of these and remote sensing to piece together studies that illustrate a broader picture of Arctic precipitation conditions and reveal emerging and/or diverging patterns of change. This chapter will (1) introduce existing and forthcoming sources of data and their corresponding challenges across the Arctic; (2) describe the distribution of precipitation characteristics including total amount, intensity, and frequency over major land areas and the oceans; and (3) demonstrate past changes and future predictions in these precipitation characteristics and their extremes. This will provide a fairly comprehensive knowledge repository and a strong foundation to promote and inspire future research development on precipitation over the Arctic region.