Precipitation observations using snow weight gauges and lysimeters

Precipitation is a critical physical quantity in a variety of disciplines and is observed globally. Ground-based observations of precipitation typically use precipitation gauges; however, various losses must be considered. Of particular note is the importance of wind-induced undercatch in the context of solid precipitation. In addition, climate change may change snowfall to rainfall, increasing the importance of accurate precipitation observations.

The objective of this study is to evaluate the accuracy of precipitation observations, including snowfall, and to provide basic information for precipitation correction methods.
The present study focuses on wind-induced undercatch loss and estimates the capture rate of precipitation gauges by comparing them with observations from snow-weight gauges and lysimeters. This approach differs from the commonly used double-fence intercomparison reference.

These observations were made in a mountainous area of Japan (Hokkaido, 439 m above sea level) and included observations other than precipitation.
In addition, observations were made during the summer season to estimate the capture rate for precipitation.

Precipitation was verified by careful comparison of precipitation gauge readings with lysimeter readings and snow weight meter increments.
The study site is located in one of the snowiest regions of the world.
The region's water resources are primarily derived from the snowpack, underscoring the need for accurate snowpack estimates.
The measurement period began in November 2023 and data through mid-April 2025 are used in the following presentation.

The effectiveness of the lysimeter in capturing precipitation was found to be approximately 95%, a result consistent with previous studies conducted in Japan.
The cumulative capture rate (for the entire winter) for snowfall was about 60%, which is reasonable.
The presentation will also include a comparison with the capture rate estimate by Yokoyama (2003).