Chukchi/Beaufort Seas Surface Wind Climatology, Variability, and Extremes from Reanalysis Data:...
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Chukchi/Beaufort Seas Surface Wind Climatology, Variability, and Extremes from Reanalysis Data: 1979- 2009 Xiangdong Zhang, Jeremy Krieger, Paula Moreira,
Chukchi/Beaufort Seas Surface Wind Climatology, Variability,
and Extremes from Reanalysis Data: 1979- 2009 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
Slide 2
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
Slide 3
Dynamic control of the large-scale surface wind Aleutian low
Beaufort high Icelandic low Siberian high
Slide 4
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
Slide 5
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
Slide 6
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
Slide 7
Arctic Rapid change Pattern (ARP) ARP Atmospheric circulation
pattern has shifted (climate systems became more unstable)
Slide 8
Dynamic control of surface wind has changed
Slide 9
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)
Slide 10
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
Slide 11
Wind has tremendous local features beyond large-scale Dynamic
control Single synoptic weather system can brings large impact on
ocean and sea ice
Slide 12
Wind has tremendous local features beyond large-scale Dynamic
control Large differences can occur in difference locations no
matter how close they are
Slide 13
Wind has tremendous local features beyond large-scale Dynamic
control Large differences can occur in difference locations no
matter how close they are
Slide 14
Data: North American Regional Reanalysis (NARR) from 1979- 2009
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
Slide 15
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
Slide 16
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
Slide 17
Obvious seasonality over the Beaufort/Chukchi seas; The largest
variance occur in October. Monthly climatology of wind speed
variances
Slide 18
Obvious seasonality over the Beaufort/Chukchi seas; The largest
variance occur in October. Monthly climatology of 95 th percentile
wind speed variances
Slide 19
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
Slide 20
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
Slide 21
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
Slide 22
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
Slide 23
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
Slide 24
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
Slide 25
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
Slide 26
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
Slide 27
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
Slide 28
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
Slide 29
JAMSTEC ship, 2009 Extreme/strong wind event induced by intense
mesoscale system
Slide 30
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