Sea Ice Historical Forecast Project (Ice-HFP)

• Main Authors: Flato, Greg, Woo-Sung Lee, Merryfield, William
• Format: Dataset
• Language: English
• Published: Canadian Cryospheric Information Network 2012
• Subjects: Arctic Ocean; Climatic models; Forecast; Integrated Regional Impact Studies; Sea ice; Beaufort Regional Environmental Assessment; Arctic; Canada; North Atlantic
• Online Access: https://dx.doi.org/10.5443/11450; https://www.polardata.ca/pdcsearch/?doi_id=11450

The key component of this project is the comparison of an experiment fully initialized to observed sea ice concentration with another experiment where sea ice initialization is climatological in nature. To properly assess the influence of sea ice initialization on summer and winter season predictions, as well as the autumn sea ice minimum, start dates for historical forecasts around a central analysis of May 1st, Aug. 1st, and Nov. 1st for the years 1996 and 2007 should be provided. The model runs through a 12-month integration. Ten ensemble members per start date were achieved. The model monthly mean outputs are as follows: 2m temperature, sea surface temperature, 2m specific humidity, (10m) velocity, mean sea level pressure, surface pressure, total precipitation, downward surface solar radiation, net surface longwave radiation, latent and sensible heat flux, and geopotential height, temperature and velocity at 850, 500, 200 and 100 hPa. Sea surface temperature and salinity, sea level height, ocean 3D temperature, 3D salinity, 3D velocity, surface heat flux, freshwater flux, momentum fluxes, ice concentration, ice thickness, snow thickness, ice velocity, ice top and bottom boundary heat, freshwater and momentum fluxes, ice top and bottom boundary temperature, snow cover, snow depth, and soil wetness. The model daily mean outputs are as follows: maximum/minimum 2m temperature, geopotential height and temperature at 850, 500, 200 and 100hPa, ice concentration, and ice thickness. More information about the datasets is available in the README file (README_IceHFP_Arctic_Ocean_29fev2012.txt). : Purpose: Tremendous advance in improving and exploiting the initialization of the oceanic and atmospheric components of seasonal forecast systems has been made in the past decade, particularly with the advent of enhanced knowledge of the world's oceans through ARGO. Utilizing the increased knowledge of sea ice conditions within seasonal prediction systems remains an untapped and unknown reservoir of potential predictability. Current seasonal prediction systems range from prescribed sea ice climatologies to fully thermodynamic and dynamic interactive sea ice initialized from an observed state. To gain understanding of the potential impact of sea ice initialization on the atmosphere, it is necessary to perform model comparisons with and without sea ice initialization. There have been suggestions that winter pre-conditioning and anomalous spring sea ice extent could influence Northern Hemisphere circulation. Effects on the location of the summertime North Atlantic Storm Track (Balmeseda et al., 2010) and the winter time circulation (e.g. Francis et al., 2009) have both been suggested. However, it is not yet known if these effects are robust and in particular whether the initialisation of sea-ice can improve predictions of seasonal climate variability. We suggest a concise set of multi-model sensitivity experiments to examine the effects of sea ice initialization in seasonal prediction systems. The experiments are a simple test of initializing sea ice conditions with the observed sea ice state versus initializing with a climatology. All other components of the seasonal prediction system would be initialized identically across the two experiments. As usual, no use of any future information should be allowed in any of the system components. Although the scope of this proposal favours the use of interactive ice models, it should not be seen as excluding simplistic statistical modelling of ice -- for instance the influence of prescribing persisted sea ice anomalies versus prescribing climatology. The primary goal of the study is to demonstrate the influence of proper initialization of sea ice on atmospheric circulation. : Summary: Forecasting agencies including Environment Canada produce long-range forecasts of seasonally averaged conditions up to a year or so in advance using climate models that represent the detailed interactions of the atmosphere, ocean, land, and sea ice. Year-to-year changes in sea ice conditions such as have been occurring dramatically in recent years undoubtedly affect climate, particularly at high northern latitudes. However, the nature of such effects and how they are represented in seasonal forecast models has not been studied in detail thus far. The Sea Ice Historical Forecast Project (Ice-HFP) was initiated to provide a framework for such an investigation. This dataset represents Canada's contribution to IceHFP.