The coastal streamflow flux in the Regional Arctic System Model

Abstract

The coastal streamflow flux from the Arctic drainage basin is an important driver of dynamics in the coupled ice‐ocean system. Comprising more than one third of the total freshwater flux into the Arctic Ocean, streamflow is a key component of the regional and global freshwater cycle. To better represent the coupling of the streamflow flux to the ocean, we have developed and applied the RVIC streamflow routing model within the Regional Arctic System Model (RASM). The RASM is a high‐resolution regional Earth System Model whose domain includes all of the Arctic drainage basin. In this paper, we introduce the RVIC streamflow routing model, detailing its application within RASM and its advancements in terms of representing high‐resolution streamflow processes. We evaluate model simulated streamflow relative to in situ observations and demonstrate a method for improving model performance using a simple optimization procedure. We also present a new, spatially and temporally consistent, high‐resolution data set of coastal freshwater fluxes for the Arctic drainage basin and surrounding areas that is based on a fully coupled RASM simulation and intended for use in Arctic Ocean modeling applications. This data set is evaluated relative to other coastal streamflow data sets commonly used by the ocean modeling community. We demonstrate that the RASM‐simulated streamflow flux better represents the annual cycle than existing data sets, especially in ungauged areas. Finally, we assess the impact that streamflow has on the coupled ice‐ocean system, finding that the presence of streamflow leads to reduced sea surface salinity, increased sea surface temperatures, and decreased sea ice thickness.

Effects of Model Resolution and Ocean Mixing on Forced Ice‐Ocean Physical and Biogeochemical Simulations Using Global and Regional System Models

“…The RASM sea ice and ocean physical model results have been validated in various previous studies (Cassano et al, ; DuVivier et al, ; Hamman et al, ; Roberts et al, ). However, since the marine ecosystem model results are significantly affected by the simulated sea ice and ocean physical environments, we also include physical model validations and comparisons.…”

“…In this study, we use the ice‐ocean model components of RASM in its native regional domain grid (e.g., Cassano et al, ; Hamman et al, ; Roberts et al, ) and in a global domain grid from CESM. The RASM domain (Figure ) covers the entire Northern Hemisphere marine cryosphere, major oceanic inflow and outflow pathways, with optimal extension into the North Pacific and Atlantic oceans to account for the origin and passage of cyclones over marginal ice zones and into the Arctic.…”

Dual state/rainfall correction via soil moisture assimilation for improved streamflow simulation: Evaluation of a large-scale implementation with SMAP satellite data

“…The local runoff simulated by VIC at each grid cell was routed through the stream channels using the RVIC routing model [Hamman et al, 2017]. RVIC is an adapted version of the routing model developed by Lohmann et al [1996Lohmann et al [ , 1998].…”

Evaluation of the atmosphere–land–ocean–sea ice interface processes in the Regional Arctic System Model version 1 (RASM1) using local and globally gridded observations

“…This reduced sea ice extent decreases the surface albedo, initiating a positive feedback in which the surface is warmed by an increase in absorbed solar radiation. This further enhances sea ice melt (Hartmann, 1994) by producing more first-year sea ice, which is thinner and easier to melt in spring (Stroeve et al, 2012). This positive feedback causes warming to be highest in the Arctic, a process that has been termed Arctic amplification (Holland and Bitz, 2003;Johanssen et al, 2004;Serreze and Francis, 2006;Serreze et al, 2009).…”