Science and Data Needs in an Era of Changing Climate

By James Partain, Chief

Environmental and Scientific Services Division

NOAA's National Weather Service

Alaska Region Headquarters

Alaska is experiencing significant climate change. Observed data indicate that mean annual temperature across Alaska has increased more than 1.2 ˚C since 1971, with sites like Barrow experiencing more than a 2 ˚C increase. Arctic sea ice records show an approximate decrease of 8% in aerial extent since 1954. In fact, the extent of arctic sea ice as of September 1, 2004, was more than 13% less than normal. Winter freeze-up and spring melt are arriving about three weeks later and earlier, respectively. A seasonal increase in thaw depth of the active ground layer is causing accelerated permafrost thaw. Melting glaciers create fresh-water ice-dammed lakes that are suddenly, and often catastrophically, released when the glaciers retreat.

The most significant impact of changing climate for the NWS in Alaska is on the short-term forecast and warning process. With more arctic coastal communities in Alaska with low coastal relief experiencing greater risk of coastal erosion and flooding from coastal storms, forecasters must provide high quality forecasts and warnings with greater lead time to emergency managers and decision makers prior to the storms…storms that are increasing in frequency and impact. The forecaster needs numerical model output for the Alaska arctic that predicts the general track, intensity, and timing of the storm and its attendant storm surge with consistency of the models from one run to the next.

The issues described above raise the following science and data needs for the NWS Alaska Region:

• Since numerical models rely on observational data there is a need for increased number and quality of arctic atmospheric and oceanic observations, both in situ and remotely sensed.

• An ocean wind and wave climatology is needed for the Bering, Chukchi, and western Beaufort Seas (research collaboration).

• Access to and analysis of very high resolution remotely sensed environmental and spatial data (e.g. MODIS, ASTER) is needed to assess the potential for and impacts of phenomena such as shore erosion, flooding, and glacier-dammed lake releases

• A more definitive analysis of climate zones in Alaska is needed so that climate tools such as compositing and down-scaling can be used to provide high quality information to climate decision-makers. [Compositing uses historical data which can be broken down or categorized into a conditional probability of a local climate variable being impacted by a regional climate variability phenomenon. Down-scaling is the correlation of a regional climate forecast parameter to a specific site based on historical data.]

• An improvement to numerical weather prediction and ocean models is needed to incorporate and better handle high latitude meteorology, and to make the most optimal use of the observational data in the arctic. This will require collaboration with the model research community.

• An analysis of arctic and sub-arctic storm source, storm track, and storm intensity is needed for the period of 1970 to present. There is evidence of storm change occurring in Alaska over this period.

• An analysis of wind speed and direction is needed for the period of 1970 to present to determine changes in predominant wind speed and direction for first order stations.

• There is need for workshops where a mix of experts in research and operations can discuss status and future high latitude short-term and climate studies, products and services.

• Decision-support tools that are GIS-based and readily accessible by the decision makers (first responders, state emergency managers, city and state planners, FEMA, etc) are needed that allow combining seasonal forecasts with planning information. Planners must stage water, fuel and food in remote Alaska villages based on such forecasts. Other long-range planners and policy makers need multi-year information in order to plan for moving coastal villages imperiled by recent coastal erosion events.