Conservation of heat in the Coupled Arctic Prediction System (CAPS v1.1): comprehensive model evaluation based on the MOSAiC observations
- 1Sun Yat-sen University (Guangzhou, China)
Abstract
Atmosphere–sea ice–ocean interactions are vital for understanding past and future changes in the Arctic climate system. Consistent heat-flux exchange across model-component interfaces is essential for investigating these interactions with coupled models on longer timescales. Here, we present the improved version of the Coupled Arctic Prediction System (CAPS), in which heat-flux exchange between the atmosphere (WRF) and ocean–sea ice (ROMS–CICE) components is made consistent across coupling interfaces. A set of pan-Arctic simulations covering the period of Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) were conducted with the revised CAPS. The revised coupling substantially reduces interfacial heat-flux residuals and improves the simulation of Arctic sea-ice conditions relative to the original coupling, which produces enhanced winter ice growth and reduced summer ice retreat during the 14-month simulation. CAPS was further evaluated against comprehensive MOSAiC observations of the atmosphere, ocean, snow, and sea ice. The model reproduces the broad evolution of Arctic conditions along the MOSAiC drift, although biases remain, partly associated with errors in simulated synoptic systems and unresolved polar physical processes. The constrained-atmosphere experiment with spectral nudging shows improved agreement with observations in several quantitative metrics, particularly for atmospheric profiles and ocean temperature. However, sensitivity experiments indicate that these improvements depend on the vertical extent and strength of nudging and should not be attributed to the revised coupling or model physics alone. Remaining biases in atmospheric humidity, surface turbulent heat fluxes, snow accumulation, and ocean salinity highlight priorities for further development of atmospheric boundary-layer, cloud radiation, snow/sea ice, and coupled surface processes in CAPS and other Arctic prediction systems.
Versions
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BibTeX
@article{yang2026conservation,
title = {{Conservation of heat in the Coupled Arctic Prediction System (CAPS v1.1): comprehensive model evaluation based on the MOSAiC observations}},
author = {Chao-Yuan Yang and Fengguan Gu and Jiping Liu and Annette Rinke and Hu Yang and Xiaoxu Shi},
journal = {Geoscientific Model Development},
year = {2026},
month = nov,
doi = {10.5194/gmd-19-10595-2026},
url = {https://gmd.copernicus.org/articles/19/10595/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Conservation of heat in the Coupled Arctic Prediction System (CAPS v1.1): comprehensive model evaluation based on the MOSAiC observations
AU - Chao-Yuan Yang
AU - Fengguan Gu
AU - Jiping Liu
AU - Annette Rinke
AU - Hu Yang
AU - Xiaoxu Shi
PY - 2026
DA - 2026/11/09
JO - Geoscientific Model Development
DO - 10.5194/gmd-19-10595-2026
UR - https://gmd.copernicus.org/articles/19/10595/2026/
AB - Atmosphere–sea ice–ocean interactions are vital for understanding past and future changes in the Arctic climate system. Consistent heat-flux exchange across model-component interfaces is essential for investigating these interactions with coupled models on longer timescales. Here, we present the improved version of the Coupled Arctic Prediction System (CAPS), in which heat-flux exchange between the atmosphere (WRF) and ocean–sea ice (ROMS–CICE) components is made consistent across coupling interfaces. A set of pan-Arctic simulations covering the period of Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) were conducted with the revised CAPS. The revised coupling substantially reduces interfacial heat-flux residuals and improves the simulation of Arctic sea-ice conditions relative to the original coupling, which produces enhanced winter ice growth and reduced summer ice retreat during the 14-month simulation. CAPS was further evaluated against comprehensive MOSAiC observations of the atmosphere, ocean, snow, and sea ice. The model reproduces the broad evolution of Arctic conditions along the MOSAiC drift, although biases remain, partly associated with errors in simulated synoptic systems and unresolved polar physical processes. The constrained-atmosphere experiment with spectral nudging shows improved agreement with observations in several quantitative metrics, particularly for atmospheric profiles and ocean temperature. However, sensitivity experiments indicate that these improvements depend on the vertical extent and strength of nudging and should not be attributed to the revised coupling or model physics alone. Remaining biases in atmospheric humidity, surface turbulent heat fluxes, snow accumulation, and ocean salinity highlight priorities for further development of atmospheric boundary-layer, cloud radiation, snow/sea ice, and coupled surface processes in CAPS and other Arctic prediction systems.
SN - 1991-9603
ER -