Preprints
https://doi.org/10.5194/tc-2021-15
https://doi.org/10.5194/tc-2021-15

  22 Jan 2021

22 Jan 2021

Review status: this preprint is currently under review for the journal TC.

Implementation of dynamic snow density within GlobSnow snow water equivalent retrieval methodology

Pinja Venäläinen, Kari Luojus, Juha Lemmetyinen, Jouni Pulliainen, Mikko Moisander, and Matias Takala Pinja Venäläinen et al.
  • Finnish Meteorological Institute, PO Box 503, FIN-00101 Helsinki, Finland

Abstract. Snow water equivalent (SWE) is an important variable in describing global seasonal snow cover. Traditionally, SWE has been measured manually at snow transects or using observations from weather stations. However, these measurements have a poor spatial coverage, and a good alternative to in-situ measurements is to use spaceborne passive microwave observations, which can provide global coverage at daily timescales. The reliability and accuracy of SWE estimates made using spaceborne microwave radiometer data can be improved by assimilating radiometer observations with weather station snow depth observations as done in the GlobSnow SWE retrieval methodology. However, one possible source of uncertainty in the GlobSnow SWE retrieval approach is the constant snow density used in modelling the emission of snow. In this paper, three versions of spatially and temporally varying snow density fields were implemented using snow transect data from Eurasia and Canada and automated snow observations from the USA. Snow density fields were used to post-process the baseline GlobSnow v.3.0 SWE product. Decadal snow density information, i.e. fields where snow density for each day of the year was taken as the mean calculated for the corresponding day over ten years, was found to produces the best results. Overall, post-processing GlobSnow SWE retrieval with dynamic snow density information improved overestimation of small SWE values and underestimation of large SWE values, though underestimation of SWE values larger than 175 mm was still significant.

Pinja Venäläinen et al.

Status: open (until 19 Mar 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2021-15', Anonymous Referee #1, 23 Feb 2021 reply
  • RC2: 'Comment on tc-2021-15', Anonymous Referee #2, 24 Feb 2021 reply

Pinja Venäläinen et al.

Pinja Venäläinen et al.

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Short summary
Information about snow water equivalent (SWE) is needed in many applications, including climate model evaluation and forecasting fresh water availability. Spaceborne radiometer observations combined with ground snow depth measurements can be used to make global estimates of SWE. In this study, we investigate the possibility of using sparse snow density measurement in satellite-based SWE retrieval, and show that using the snow density information in post-processing improves SWE estimations.