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Abstract

The Svalbard archipelago, in the Atlantic-Arctic region, was affected by a strong warming in the last decades. As a consequence, major rainfall events occurred in the last years, even during the boreal winter, with major impacts for the Arctic ecosystem. Ny-Ålesund, in the northwest part of Svalbard, is known as the northernmost town of the world and hosts major research works for Svalbard and the Arctic. In this context, the long meteorological records (1975-) from Ny-Ålesund are widely used by many research. However, the amount of precipitation recorded by this station is subjected to large biases, mainly due to a snow undercatch during windy conditions. The purpose of this study is to investigate if the measured trend of precipitation observed in Ny-Ålesund in the 1975-2022 period was real, or if it can be due to a rain gauge undercatch. In this work, we selected several correction factors developed in the last decades, based on local wind and temperature. We applied these corrections to the 12-hourly precipitation data from Ny-Ålesund weather station in the 1975-2022 period. For each correction method, we calculated trends for nine periods of 40 years (1975-2014 to 1983-2022). The results show that despite an actual decrease of precipitation in the last few years, the strong recent warming increased the rainfall to snowfall ratio, artificially enhancing the most recent observed trends of precipitation. This study shows the need of applying corrections factors when using rain gauge data, especially in periods of rapid interannual change of weather conditions.