Chukchi/Beaufort Seas Surface Wind Climatology, Variability, and Extremes from Reanalysis Data: Xiangdong Zhang, Jeremy Krieger, Paula Moreira, and Soumik Basu IARC and ARSC, University of Alaska Fairbanks Jing Zhang, and Steve Stegall NOAA-ISET Center, North Carolina A&T State University Martha Shulski High Plains Regional Climate Center, University of Nebraska-Lincoln

Outlines Large scale control Synoptic and mesoscale features beyond the large-scale control Regional data analysis results  ~ 20-25% of variance  provide background information to mesoscale model  rapid changes in wind speed and direction

Dynamic control of the large-scale surface wind Aleutian low Beaufort high Icelandic low Siberian high

Large-scale modulation: Beaufort high intensifies/weak ens, and shifts with AO fluctuation. Arctic Oscillation shows a large fluctuations and an upward trend from 1970s to 90s. Thompson and Wallace (1998) Positive AO Negative AO Dynamic control of the large-scale surface wind

Xiangdong Zhang et al. (2003) Differences of Surface Air Temperature and Wind Stress Between Positive and Negative AO Dynamic control of the large-scale surface wind

Differences of Sea Ice Properties Between Positive and Negative AO Concentration and VelocityThickness Zhang et al. (2003) Arctic Oscillation largely impacts sea ice and ocean

Arctic Rapid change Pattern (ARP) ARP Atmospheric circulation pattern has shifted (climate systems became more unstable)

Dynamic control of surface wind has changed

Swift phase change of ARP accelerated climate change and resulted in the extreme event of sea ice cover loss in summer 2007 ARP Index (All Months Included)

The ARP associated atmospheric and oceanic heat transport reduced sea ice and enlarged open water Extreme sea ice loss in summer 2007 is a result of multiyear polarity and swift phase change of ARP, not a single-time, random event The previously warmed ocean retains the decreased sea ice The enlarged open water enhance albedo feedback The ARP phase change reversed wind pattern and reduced sea ice cover The ARP phase change enhanced Pacific warm air and warm water inflow The enlarged open water enhance albedo feedback

Wind has tremendous local features beyond large-scale Dynamic control Single synoptic weather system can brings large impact on ocean and sea ice

Wind has tremendous local features beyond large-scale Dynamic control Large differences can occur in difference locations no matter how close they are

Wind has tremendous local features beyond large-scale Dynamic control Large differences can occur in difference locations no matter how close they are

Data: North American Regional Reanalysis (NARR) from with 32 km grid spacing, and 8 times daily. Parameters to be analyzed: 1.Climatology of wind speeds; 2.Climatology of 95 th percentile wind; 3.Climatology of wind directions. Regional analysis of wind field

Obvious seasonality over the Beaufort/Chukchi seas; Minimum wind speeds occur in May; Maximum wind speeds occur in September and October (~7-8 m/s or greater). Monthly climatology of wind speeds

Similar seasonality to the averaged wind speeds; Minimum wind speeds occur in May; Maximum wind speeds occur in September and October (~14-15 m/s or greater). Monthly climatology of 95 th percentile of wind speeds

Obvious seasonality over the Beaufort/Chukchi seas; The largest variance occur in October. Monthly climatology of wind speed variances

Obvious seasonality over the Beaufort/Chukchi seas; The largest variance occur in October. Monthly climatology of 95 th percentile wind speed variances

NE wind dominates over the Beaufort/Chukchi seas; The largest frequency occurs in winter and spring (larger than 60%). Monthly climatology of frequency of NE wind

SE wind mainly occurs over the northwest Beaufort Sea and Chukchi Sea; The largest frequency occurs in early summer. Monthly climatology of frequency of SE wind

SW wind mainly occurs over the north Beaufort Sea and Canada Basin; The largest frequency occurs in late summer. Monthly climatology of frequency of SW wind

NW wind mainly occurs over the north of the Canadian Archipelago, and Siberian coast of the Chukchi Sea; The largest frequency occurs in winter (over 60%). Monthly climatology of frequency of NW wind

NW wind mainly occurs over the north of the Canadian Archipelago, and Siberian coast of the Chukchi Sea; The largest frequency occurs in winter (over 60%). Monthly climatology of frequency of NW wind

Wind speed generally has increased in the Beaufort and Chukchi seas throughout most of the year; The largest increase has occurred in September and October (90% significant level in the hatching area). Linear trends of wind speeds

Similarly, wind speed generally has increased in the Beaufort and Chukchi seas throughout most of the year; The largest increase has occurred in September and October (90% significant level in the hatching area). Linear trends of the 95 th percentile wind speeds

The wind speed had large fluctuations year by year in the Beaufort and Chukchi seas; The largest increase has occurred from July to October. Linear trends of wind speed time series

Similarly, the wind speed considerably fluctuated in the Beaufort and Chukchi seas throughout the year; The largest increase has occurred from July to October. Linear trends of the 95 th percentile wind speed time series

Strong seasonality occurs for the diurnal cycle of wind speeds; Wind speeds have larger diurnal cycle in March and April over ocean, and from April through September over land. Diurnal cycle of surface wind speeds

JAMSTEC ship, 2009 Extreme/strong wind event induced by intense mesoscale system

Atmospheric circulation plays a dynamic controlling role in surface wind variability and changes; Surface wind has strong local and mesoscale features beyond the large-scale circulation control; The monthly averaged and the 95 th percentile of 8 hourly surface wind speeds present a large seasonality with a minimum in May and a maximum in September and October; The monthly averaged and the 95 th percentile of 8 hourly surface wind speeds has considerable increased in September and October during the last 30 years; Wind speeds show clear diurnal cycle in March and April over ocean and from April through September over land. Summary