The GOddard SnoW Impurity Module (GOSWIM) for the NASA GEOS-5 Earth System Model: Preliminary Comparisons with Observations in Sapporo, Japan

Abstract

The snow darkening module evaluating dust, black carbon (BC), and organic carbon (OC) depositions on the mass of snow impurities and albedo has been developed for the NASA Goddard Earth Observing System, Version 5 (GEOS-5) Earth System Model, as the GOddard SnoW Impurity Module (GOSWIM). GOSWIM consists of the updated snow albedo scheme from a previous study (Yasunari et al. 2011) and a newly developed mass concentration calculation scheme, directly using aerosol depositions from the chemical transport model (GOCART) in GEOS-5. Compared to observations at Sapporo, the off-line simulations, forced by observation-based meteorology and aerosol depositions from GOES-5, reasonably simulated the seasonal migration of snow depth, albedos, and impurities of dust, BC, and OC in the snow surface. However, the simulated dust and BC mass concentrations in snow were especially underestimated except for the BC in the early winter, compared to the observations. Increasing the deposition rates of dust and BC could explain the observations. Removing BC deposition could possibly lead to an extension of snow cover duration in Sapporo of four days. Comparing the offline GOSWIM and the GEOS-5 global simulations, we found that determining better local precipitation and deposition rates of the aerosols are key factors in generating better GOSWIM snow darkening simulation in NASA GEOS-5.(Citation: Yasunari, T.

Impact of snow darkening via dust, black carbon, and organic carbon on boreal spring climate in the Earth system

“…The Catchment Land Surface Model [ Ducharne et al ., ; Koster et al ., ] in GEOS‐5 uses the snowpack model of Lynch‐Stieglitz [], and GOSWIM follows the constituent tracers through each of the snow model's three layers (see Figure 1 of Yasunari et al . []). We perform two sets of simulations, one with dust, BC, and OC constituents in snow and one without them; we then compare these sets of simulations to quantify the impact of the constituents on boreal spring climate (see the descriptions mentioned later).…”

“…The 32 deposition variables from GOCART included wind‐generated dust, BC from anthropogenic and natural sources including fossil fuel and biomass burning, and OC from the BC sources and from biogenic emission, sent to the snow surface through dry deposition, large‐scale and convective scavenging (wet), and gravity sedimentation (dust only) [ Chin et al ., , ; Ginoux et al ., ; Colarco et al ., ]; also, see some descriptions on the used emission data in Yasunari et al . [, and references therein]. Once deposited on the snow surface, the nine constituent tracers are followed through the snow using GOSWIM [ Yasunari et al ., ], as discussed below.…”

“…[, and references therein]. Once deposited on the snow surface, the nine constituent tracers are followed through the snow using GOSWIM [ Yasunari et al ., ], as discussed below.…”

“…Yasunari et al . [] examined the variations of snow‐related variables caused by dust+BC+OC SDE over a single winter at a single location (Sapporo, Japan) based on results from off‐line land surface model and online global simulations constrained by the prescribed meteorological fields. Their results showed that with reasonable meteorological and aerosol deposition inputs, GOddard SnoW Impurity Module (GOSWIM) simulated reasonably well the evolution of the snowpack and its concentrations of impurities (i.e., dust, BC, and OC) in the top snow layer over a full winter cycle.…”

The impact of atmospheric mineral aerosol deposition on the albedo of snow & sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?

“…Chýlek et al, 1983;Warren, 1984;Clarke and Noone, 1985;Warren and Clarke, 1990;Grenfell et al, 2002;Lee Taylor and Madronich, 2002;Jacobson, 2004;Flanner et al, 2007;Doherty et al, 2010;Reay et al, 2012;Ye et al, 2012;King, 2013, 2014). Field observations and modelling simulations have also shown that increases in dust deposition to snow lead to radiative forcing that affects the energy balance of snow (Woo and Dubreuil, 1985;Aoki et al, 1998;Painter et al, 2007Painter et al, , 2012Huang et al, 2011;Wang et al, 2013;Zhang et al, 2013;Zhao et al, 2014;Yasunari et al, 2014). However, although anthropogenic deposits in polar snow and ice have been well characterised, studies on the effects of natural mineral aerosol deposits are more scarce.…”