National Aeronautics and Space Administration

National Climate Assessment

NASA National Climate Assessment (NCA) Activities

NASA Indicators Solicitation Proposals

Development and Testing of Potential Indicators for the National Climate Assessment

Lead PI and Center: Jianhua Qian, University of Massachusetts Lowell
Title: Frequency of Winter Weather Regimes in the US Northeast as an Indicator for National Climate Assessment

The NASA Modern-Era Retrospective analysis for Research and Application (MERRA) data will be used for a long-term daily weather typing (WT) analysis for the US Northeast (NE). The focus of the WT analysis is on the frequency of the east coast winter weather regimes, especially the extreme northeasters (nor'easters), which affect many socio-economic sectors in the region. The frequency of specific weather regimes (WT index) can be used for weather hazard risk assessment and energy usage assessment.

The seasonal mean climate in the east coast of US is determined by the frequency, position and intensity of various weather regimes. We will use an automated k-means clustering method to analyze the daily data of MERRA reanalysis from 1979-present to check the variability and change in the WT index.

The Intergovernmental Panel of Climate Change (IPCC) reported that global warming is more dramatic in higher latitudes than in the tropics, which therefore acts to not only increase absolute moisture in the atmosphere but also reduce atmospheric baroclinicity in terms of the equator-pole temperature gradient. Consequently, the location of storm tracks (which depends on the temperature gradient), both the east coastal storm track to the northwest of the Gulf Stream and the frontal storm track across the mid-latitude of North American Continent, could also be changed. Accordingly, this would induce change of climate zones and the timing of season. The proposed study will analyze these WT variability and change and their impacts in the cold season (October-April).

The variability and change of weather regimes directly impact people's daily lives, especially in the natural hazard risk management in the metropolitan areas on the east coast of US. Nor'easter is one type of extreme weather regime that frequently affects this region. The proposed study of WT analysis by using the MERRA reanalysis data will produce information on the frequency of the weather regimes, especially the extreme ones, in NE as an indicator for NCA.

Daily energy usage is found to be dependent on weather (clouds, temperature, etc.). The daily weather regimes obtained in this study will be compared to the daily energy usage data (currently available) to study the weather and climate impacts on the energy industry. Averaged daily energy usage corresponding to each weather types will be analyzed by composite analyses.  Long-term variability and change in energy usage will also be examined by using the WT index.