Beaufort Gyre Climate Response Function experiments: sea ice transport and freshwater content

• Main Author: Sam B. Cornish
• Format: Dataset
• Language: unknown
• Published: Arctic Data Center 2022
• Subjects: Cornish; Beaufort Sea; Sea ice
• Online Access: https://doi.org/10.18739/A20K26C63

This dataset contains the variables used in the manuscript: Cornish et al., Impact of sea ice transport on Beaufort gyre liquid freshwater content (preprint: https://doi.org/10.21203/rs.3.rs-1478152/v1). The purpose of the study was to test the hypothesis that wind-driven sea ice transport into/from the Beaufort Gyre region influences the freshwater content of the gyre and its variability. To test this hypothesis, we used the results of a coordinated climate response function (CRF) experiment with four ice-ocean models, in combination with targeted experiments using a regional setup of the Massachusetts Institute of Technology general circulation model (MITgcm), in which we rotated the surface wind forcing vectors by 10 degrees, thereby changing the ageostrophic component of these winds. The datasets here provide the outputs of all the climate model experiments used in the paper. These data can be used to acquire insights into the role of sea ice transport in influencing Beaufort Gyre freshwater content. The mechanistic links are explored in the paper. The experimental procedure involved perturbing the ice-ocean models with exactly the same 10 meter (m) wind anomaly, based on particular a sea-level pressure anomaly pattern, by adding this 10 m wind perturbation to the original forcing fields (which vary from model to model). Two anomaly patterns were used: an anticyclonic pattern that strengthens the Beaufort Sea High (BGP, for Beaufort Gyre Plus), and a cyclonic pattern that weakens the Beaufort Sea High (BGM, for Beaufort Gyre Minus). The anomalies are centred on 77 North, 149 West, with a radius of influence on the order of 1,000 kilometers (km). In these datasets, we provide outputs from the control simulations of each model (CTRL), and the BGP and BGM runs. The climate response functions are extracted as the timeseries of a variable in the anomaly run (e.g. BGP) minus the equivalent timeseries in the control run. For the MITgcm, we provide two parallel sets of experiments. Firstly, the original CRF experiment, as above, which is comprised of the model runs CTRL, BGP, and BGM. Secondly, a CRF experiment with a modification to the angle of wind vectors by 10 degrees anticlockwise only over sea ice. The modification is applied to both the background winds and the perturbation winds, and yields the runs CTRL10, BGP10, and BGM10. The 10 degree angle is considered to roughly reflect the uncertainty in the cross-isobaric angle of surface wind over sea ice. Note that only one direction of rotation is required in order to probe both ice export and import scenarios, given that this angular adjustment is applied to anomalies with both senses of rotation: anticyclonic and cyclonic, and we can extract the effect of changing the sea ice dynamics (ice import and export) by comparing against the original perturbation experiments (which have no such modification to the surface winds). CRFs are calculated using the respective control and perturbation runs for each experiment.