HUMAN-ASSOCIATED EXTREME EVENTS: FREEZING PRECIPITATION Pavel - - PowerPoint PPT Presentation

HUMAN-ASSOCIATED EXTREME EVENTS: FREEZING PRECIPITATION

Pavel Groisman1,4,6, Xungang Yin2, Olga Bulygina3, and Irina Danilovich (Partasenok)5

(1) North Carolina State University Scholar at NOAA National Centers for Environmental Information, Asheville, North Carolina, United States (pasha.groisman@noaa.gov} (2) ERT, Inc., at NOAA National Centers for Environmental Information, Asheville, North Carolina, USA (3) All-Russian Research Institute of Hydrometeorological Information - World Data Centre, Obninsk, Russia (4) P.P. Shirshov Institute for Oceanology, Russian Academy of Sciences, Moscow, Russia (5) Center of Hydrometeorology and Control of Radioactive Contamination and Environmental Monitoring, Minsk, Belarus (6) Hydrology Science and Services Corporation, Asheville, North Carolina, USA.

Objective

(GEWEX Cross-Cut project):

To improve our understanding of future changes in hazardous cold/shoulder season precipitation and storms, especially occurring near 0°C. These extremes can be devastating and are subject to changing climate.

Rationale

Global changes in the last decades (in particular, in the 21st century) were already too large. They do not allow us to ignore their potential consequences in extreme events frequency and intensity.

Data and Brief Summary of Results

The Arctic Warming

Annual surface air temperature anomalies area- averaged over the 60°N - 90°N latitudinal zone, °C

dT/dt = 2.2°C/137 yrs; R² = 0.51

• 4.0
• 3.0
• 2.0
• 1.0

0.0 1.0 2.0 3.0 4.0 5.0 1880 1895 1910 1925 1940 1955 1970 1985 2000 2015

°C

Lugina et al. 2006, updated

Long-term synoptic stations used in our analyses; 1- and 3-hourly DATA for the past 40 years

First group are station data collected for Groisman et al.

• 2016. The second group

includes the station data that we are currently using to cover the entire extratropics. The third group includes also the upper air data for further studies of the freezing events phenomena and reanalyses.

First group

Second group

Europe, 550 stations Belarus Kyrgyzstan stations at 2 km or above are shown in red

Changes of freezing events in the last

• decade. Results in a nutshell
• Using synoptic data for the past 40 years, we estimated the

climatology of the frequency of freezing rain and drizzle

• ccurrence for North America, Europe, Russia, Belarus, and

Kyrgyzstan and their changes in the past decade

• During the last decade, substantial changes in the

annual freezing rain occurrence were found:

– On the southern edge of our study domain (southeastern U.S., Central Europe, southern Russia) the frequencies of freezing events decreased along with the duration of the cold season; – In northern Canada, Alaska, Europe and North Atlantic north

• f 60°N, Eastern Belarus, in some taiga areas of Russia, and at

high elevations (The Tian Shan Mountains), the frequencies of freezing events increased “following” the expansion of the short warm season.

• Occurrence of freezing drizzle over Russia has

decreased nationwide.

Long-term regional mean values of freezing rain frequency northern Europe and selected regions of North America and Russia for 1975-2014 and differences between the mean values for the last decade (2005-2014) and the previous 30-yr-long period (1975-2004) Region Regional mean values days yr-1 Diff. days yr-1

Significant changes by following tests

North America north of 66.7N

1.8 1.06 t- & L- tests

North America, between 50N and 60N

2.5 0.28 L- & Rs- tests

Greenland and Iceland

1.1 0.49

L- & Rs- tests

Norway south of 66.7N

1.1 1.05 all three tests

Norway north of 66.7N

1.1 1.10 all three tests

Baltic Sea Basin

2.0 0.60

all three tests

Russian Atlantic Arctic

1.4

• 0.20

L- & Rs- tests

Great East European Plain, northwest

1.3 0.28 none

Great East European Plain, northeast

2.2 0.77 L- & Rs- tests

Statistically significant changes at the 0.05 level are in bold and at the 0.10 level are in bold italic.

CLIMATOLOGY

Climatology of freezing events over North America for the 1975-1994 period

Annual freezing rain frequency Annual freezing drizzle frequency

Days Days

as reported by the NCEP Climate Forecast System

• Reanalysis. V2

(CFSRv2)

Mean annual frequency of days with freezing precipitation d ×(yr)-1

Climatology of freezing rain events over Europe, 1975-2014

Climatology of freezing events over Russia and Norway

Annual frequency of freezing rain days The same, but for freezing drizzle days

1975-2014

Climatology of all freezing events over Russia and Belarus

days Annual frequency, 1975-2014

Mean annual frequency of days with freezing precipitation over Eurasia west of the Ural Mountains; 1979-2017; d ×(yr)-1

As reported by the NCEP Climate Forecast System Reanalysis. V2 (CFSRv2)

PILOT CHARACTERIZATION OF FREEZING EVENTS USING OTHER METEOROLOGICAL VARIABLES

Freezing precipitation distribution (%) by associated surface air temperature, Ta (over entire Russia)

Freezing rain by Ta Freezing drizzle by Ta

5 10 15 20 25 30

• 20.5
• 17.5
• 14.5
• 11.5
• 8.5
• 5.5
• 2.5

0.5 3.5 6.5 9.5

5 10 15 20 25 30

• 20.5
• 18.0
• 15.5
• 13.0
• 10.5
• 8.0
• 5.5
• 3.0
• 0.5

2.0 4.5 7.0 9.5

%

Upper air normalized temperature anomalies at 700 hPa for freezing events at five US stations

• Three CONUS stations
• Two Alaskan stations
• 2.0
• 1.0

0.0 1.0 2.0 3.0

1/24/1975 1/24/1978 1/24/1981 1/24/1984 1/24/1987 1/24/1990 1/24/1993 1/24/1996 1/24/1999 1/24/2002 1/24/2005 1/24/2008 1/24/2011 1/24/2014

Three CONUS stations

1/25/1975 1/25/1978 1/25/1981 1/25/1984 1/25/1987 1/25/1990 1/25/1993 1/25/1996 1/25/1999 1/25/2002 1/25/2005 1/25/2008 1/25/2011 1/25/2014

Two Alaskan stations

Anomalies are expressed in fractions of standard deviations of “normalized” daily temperature values at 12 UTC. Seasonal cycle variability of mean daily values and variances are eliminated by

• normalizing. CONUS = Contiguous U.S.

• 2
• 1

1 2 3

1975-03-03-12 1981-03-09-12 1988-11-10-12 1983-01-23-12 1992-01-13-12 2003-01-06-12 1980-10-19-12 1991-03-11-12 1997-01-15-12 2002-02-06-12 2005-11-06-12 1983-01-12-12 1990-02-05-12 1995-11-22-12 1999-01-31-12 2001-01-07-12 2003-03-31-12 2004-12-12-12 2007-11-22-12 2012-01-11-12 1981-03-07-12 1991-12-26-12 1999-01-15-12 1977-01-03-12 1993-11-04-12 1979-11-22-12 1977-12-28-12

Upper air normalized temperature anomalies at 850 and 700 hPa for freezing events at eight stations of Fennoscandia

700 hPa Northern Europe

Anomalies are expressed in fractions of standard deviations of “normalized” daily temperature values at 12 UTC. Seasonal cycle variability of mean daily values and variances are eliminated by

• normalizing. Stations from Finland, Sweden, Norway, and Iceland.
• 2
• 1

1 2 3

1975-03-03-12 1981-03-09-12 1988-11-10-12 1983-01-23-12 1992-01-13-12 2003-01-06-12 1980-10-19-12 1991-03-11-12 1997-01-15-12 2002-02-06-12 2005-11-06-12 1983-01-12-12 1990-02-05-12 1995-11-22-12 1999-01-31-12 2001-01-07-12 2003-03-31-12 2004-12-12-12 2007-11-22-12 2012-01-11-12 1981-03-07-12 1991-12-26-12 1999-01-15-12 1977-01-03-12 1993-11-04-12 1979-11-22-12 1977-12-28-12

850 hPa Northern Europe

Upper air normalized temperature anomalies at 850 and 700 hPa for freezing events at 7 stations of East European taiga

700 hPa North European Russia

Anomalies are expressed in fractions of standard deviations of “normalized” daily temperature values at 12 UTC. Seasonal cycle variability of mean daily values and variances are eliminated by

• normalizing. Russian stations from 55°N to 62°N west of the Urals.

850 hPa North European Russia

• 2
• 1

1 2 3

1976-02-20-12 1984-12-03-12 2011-11-06-12 1996-01-18-12 2006-01-06-12 2011-12-26-12 1976-12-07-12 1982-01-18-12 1985-12-22-12 1995-01-15-12 1977-02-24-12 1982-12-28-12 2008-12-12-12 1976-02-26-12 1978-02-16-12 1982-11-28-12 1985-01-08-12 1987-11-28-12 1991-03-19-12 1993-01-09-12 1997-01-23-12 2007-12-06-12 2011-01-18-12 1998-02-28-12 2006-12-22-12 1978-01-02-12 1984-03-27-12 2005-02-17-12

• 2
• 1

1 2 3

1976-02-20-12 1984-12-03-12 2011-11-06-12 1996-01-18-12 2006-01-06-12 2011-12-26-12 1976-12-07-12 1982-01-18-12 1985-12-22-12 1995-01-15-12 1977-02-24-12 1982-12-28-12 2008-12-12-12 1976-02-26-12 1978-02-16-12 1982-11-28-12 1985-01-08-12 1987-11-28-12 1991-03-19-12 1993-01-09-12 1997-01-23-12 2007-12-06-12 2011-01-18-12 1998-02-28-12 2006-12-22-12 1978-01-02-12 1984-03-27-12 2005-02-17-12

Upper air normalized temperature anomalies at 850 and 700 hPa for freezing events at 8 stations

• f East European forest-steppe and steppe

700 hPa South European Russia

Anomalies are expressed in fractions of standard deviations of “normalized” daily temperature values at 12 UTC. Seasonal cycle variability of mean daily values and variances are eliminated by

• normalizing. Russian stations from 50°N to 54.5°N west of the Urals.

850 hPa South European Russia

• 2
• 1

1 2 3

1975-02-04-12 1993-12-26-12 2002-01-14-12 2009-03-08-12 1989-12-02-12 1997-12-31-12 2011-12-23-12 2014-02-06-12 2005-12-09-12 1976-11-29-12 1981-12-04-12 1987-12-20-12 1992-01-29-12 2000-12-04-12 2006-03-11-12 2010-12-27-12 1985-12-07-12 1994-11-20-12 1978-01-30-12 1985-11-25-12 1991-11-17-12 1999-02-16-12 2013-02-09-12 1985-12-08-12 1991-11-26-12 2002-01-12-12 2009-01-16-12

• 2
• 1

1 2 3

1975-02-04-12 1991-12-14-12 2001-02-09-12 2009-01-23-12 1976-01-02-12 1994-11-17-12 2009-02-17-12 2013-12-21-12 1997-11-14-12 2010-12-14-12 1978-03-25-12 1982-12-25-12 1989-01-20-12 1993-12-10-12 2001-02-08-12 2006-03-23-12 2010-12-27-12 1985-11-27-12 1993-01-22-12 1977-02-03-12 1983-12-23-12 1990-11-28-12 1993-12-27-12 2009-01-26-12 1979-04-06-12 1987-12-20-12 1994-01-11-12 2002-02-12-12 2009-12-27-12

Air temperatures differences between the days with freezing events and the “nearby” days (1975-2014; USA) Vertical temperature differences during the days with freezing events (850 hPa – surface; 700 hPa – 850 hPa; 500 hPa – 850 hPa). inversions

°C

Air temperatures differences between the days with freezing events and the “nearby” days (1975-2014; Fennoscandia) Vertical temperature differences during the days with freezing events (850 hPa – surface; 700 hPa – 850 hPa; 500 hPa – 700 hPa). Inversions.

°C

Air temperatures differences between the days with freezing events and the “nearby” days (1975-2014; European Russia)

Vertical temperature differences during the days with freezing events (850 hPa – surface; 700 hPa – 850 hPa; 500 hPa – 700 hPa). Inversions. °C

• 20
• 15
• 10
• 5

5

surface 850 hPa 700 hPa Temperature gradients dT (freezing - no freezing) Vertical gradient

Narian-Mar, Russia, 67.6°N

• 20
• 15
• 10
• 5

5

surface 850 hPa 700 hPa Temperature gradients dT (freezing - no freezing) Vertical gradient

GMO Kreenkelya, Russia, 81°N

• 20
• 15
• 10
• 5

5

surface 850 hPa 700 hPa Temperature gradients dT (freezing - no freezing) Vertical gradient

Saratov, Russia, 52°N

• 20
• 15
• 10
• 5

5

surface 850 hPa 700 hPa Temperature gradients dT (freezing - no freezing) Vertical gradient

Moscow, Russia,56°N

Generalized definition of weather conditions conducive to freezing rain (WCCFR) with P.

Relationship was derived from synoptic and aerologic observations in the U.S., Canada, Russia, and Northern Europe and is valid at elevations below 1200 m

Meteorological variable Boundary (ies) Near-surface air temperature, Tsurface Tsurface[-5.0°C, 0.2°C] Air temperature at 850 hPa T850hPa > -0.4°C Air temperature at 700 hPa T700hPa > -6°C

Weather conditions conducive to freezing rain (WCCFR) applied to the CFSRv2 data at elevations below 1200 m.

64% of WCCFR are classified as “Freezing Precipitation” by CFSRv2

Freezing Rain climatology, 1979-2017

68% of WCCFR are classified as “Freezing Precipitation” by CFSRv2

Freezing Rain climatology, 1979-2017

Weather conditions conducive to freezing rain (WCCFR) applied to the CFSRv2 data at elevations below 1200 m.

Weather conditions conducive to freezing rain (WCCFR) applied to the CFSRv2 data at elevations below 1200 m.

Freezing Rain climatology, 1979-2017

64% of WCCFR are classified as Freezing Precipitation” by CFSRv2

Freezing rain days change in the past 13 years (2005-2017) compared to the previous 26 years (1979-2004), %

Freezing rain days change in the past 13 years (2005-2017) compared to the previous 26 years (1979-2004), %

Freezing rain days change in the past 13 years (2005- 2017) compared to the previous 26 years (1979-2004), %

Freezing rain over China, south of 40°N

Climatology, 1979-2017; d yr-1 Changes after 2004, %

Percent distribution of freezing rain events over Russia by associated surface air temperature Ta during the 1975-2004 and post 2004 periods

• Practically no differences with time in freezing rain distribution by Ta
• 10
• 5

5 10 15 20 25 30

• 6.5 -6.0 -5.5 -5.0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

1975-2004 after 2004 Differences

Ta %

Current achievements

• Using synoptic and aerologic data, we found the

weather conditions that are mostly conducive to freezing rain (WCCFR)

• Now, these WCCFRs have been used to expand

climatology of the freezing precipitation over the northern extratropics at low elevations.

• With the probabilities of 0.64 to 0.68 (depending

upon the region), the WCCFRs characterize the “actual” freezing precipitation events reported by the CFSRv2 reanalysis.

• The algorithm of the WCCFR evaluation can be used

for the FR spatial and future projections (e.g., within the reanalyses and future climate change scenarios).

Need to fu further study of fr freezing precipitation at high elevations

• Changes here can be very different (cf.,

Kyrgyzstan, next slide)

• Freezing events here are quite frequent even in

dry climates (cf., Western N. America and Tibetan Plateau, last slide)

Freezing events at different elevation below 1 km from 1 to 2 km above 2 km Climatology, days(yr)-1 0.98 0.61 0.25 Changes between two periods, days(yr)-1

• 0.31
• 0.16

0.50

Annual frequency of all freezing precipitation events (freezing rain, freezing drizzle, and ice rain)

• ver Kyrgyzstan during the 1966-1990 period and

recent changes in this frequency during the 21st century

Data of 26 synoptic stations. For the 2009-2011, the data were not available for analysis

Mean annual frequency

• f days with freezing

precipitation d ×(yr)-1 as reported by

the NCEP Climate Forecast System

• Reanalysis. V2 (CFSRv2)