Snow parametrisations in COSMO-RU: analysis of winter-spring forecasts 2009-2010 COLOBOC Workshop....

Snow parametrisations in COSMO-RU:

analysis of winter-spring forecasts 2009-2010

COLOBOC Workshop. Moscow, 6 September 2010

Basic characteristics of New snow scheme

Multilayerness

Radiation is described explicitly

Description of snow compaction by metamorphism and gravity

Phase transition of liquid water in snow cover

Description of water percolation with its next freezing and release of heat


Methods and data

Comparison 2 versions model COSMO-Ru: “new” (with New snow scheme in TERRA) and “old” (previous snow scheme in TERRA)

Integration period – 78h (from 00 UTC)

Data: - station measurements - decade measurements of snow

survey on Roshydromet’s stations


Research region: European part of Russia

north

centre

south

Snow characteristics: SWE and snow depth (1.12.09-28.02.10)

0

30

60

90

120

150

180

210

1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

8

декабрь январь февраль

мм

72ч-нов

72ч-стар

станция-лес

Medvegegorsk : SWE – measurements and 72h forecasts

north

91 mm 95 mm83 mm



0

30

60

90

120

150

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28


мм

осадки снег

осадки дождь

72ч-нов

72ч-стар

станция-лес

north

16 mm

18 mm

Medvegegorsk : SWE – measurements and 72h forecasts without mistakes



0

30

60

90

120

150

180

210

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28


мм

72ч-нов

72ч-стар

станция-поле

centre

70 mm81mm

108mm

Inza : SWE – measurements and 72h forecasts



0

30

60

90

120

150

1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

8


мм



72ч-нов

72ч-стар


centre

0

037mm

Inza : SWE – measurements and 72h forecasts without mistakes


0

30

60

90

120

150

180

210

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28


мм

72ч-нов

72ч-стар



south

Harabaly : SWE – measurements and 72h forecasts



0

30

60

90

120

150

1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

8


мм



72ч-нов

72ч-стар


south

Harabaly : SWE – measurements and 72h forecasts without mistakes



station new old

Verhnyaya Toyma 0,89 0,94

Krasnoborsk 0,88 0,95

Lalsk 0,90 0,92

Medvegegorsk 0,92 0,96

Pinega 0,92 0,94

Correlation coefficients for snow depth according station data and 72h forecasts

station new old

Blagodarniy 0,84 0,85

Verhniy Baskunchak 0,55 0,42

Modok 0,87 0,72

Nalchik 0,77 0,65

Prohladnaya 0,86 0,78

Harabaly 0,89 0,84

north

south

station new old station new old

Anna 0,81 0,84 Kolomna 0,92 0,94

Bologoe 0,93 0,94 Michurinsk 0,90 0,96

Buzuluk 0,93 0,93 Mogga 0,90 0,95

Buy 0,87 0,92 Morshansk 0,94 0,96

Vetluga 0,85 0,94 Poniri 0,85 0,90

Gotnya 0,81 0,86 Radishevo 0,96 0,96

Dmitrov 0,94 0,95 Rybinsk 0,92 0,97

Inza 0,95 0,95 Rilsk 0,83 0,86

Kamishin 0,86 0,94 Spas-Demensk 0,92 0,95

Karabulak 0,91 0,90 Urupinsk 0,75 0,77

Karachev 0,91 0,97 Frolovo 0,78 0,69

centre

-10-505

101520253035404550556065707580859095

100105110115

1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

1 1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

8


см

осадки снег, мм

осадки дождь, мм

станция

72ч-нов

72ч-стар

(Т+100С), 12UTC

05

101520253035404550556065707580859095

100105110115

1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31 1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31 1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28


см



станция

72ч-нов

72ч-стар

(Т+100С), 12UTC

00С

00С

-10-505

101520253035404550556065707580859095

100105110115

1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31 1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31 1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28


см



станция

72ч-нов

72ч-стар

(T+100C), 12 UTC

00С

Snow depth

north

centre

south

T2m (11.03.-29.03.09)

-14,0-12,0-10,0-8,0-6,0-4,0-2,00,02,04,0

11 м

арта

13 м

арта

15 м

арта

17 м

арта

19 м

арта

21 м

арта

23 м

арта

25 м

арта

27 м

арта

29 м

арта

дата

0С

станция

прогноз на 24ч

прогноз на 24ч-нов

-14,0-12,0-10,0-8,0-6,0-4,0-2,00,02,04,0

дата

0С

станцияпрогноз на 24чпрогноз на 24ч-нов

Kursk Moscow

night

-6,0-4,0-2,00,02,04,06,08,0

10,012,0

дата

0С

станция



-6,0-4,0-2,00,02,04,06,08,0

10,0

дата

0С

станция



Kursk Moscow

day


T2m (29.03.10)

Snow fractional cover

))_

,0.1min(,01.0max(snowcf

zwsnowzrss

zrss - ice covered part of grid element

zwsnow - SWE

snowcf _ - parameter

1_

snowcf

zwsnow 1_

snowcf

zwsnow

Differences between forecasts with “standard” cf=0.015m and cf=0.05m

Day 1 Day 2

Snow depth

T2m

T2m (29.03.10). Experiments

мsnowcf 05.0_

CT 02,0if then мsnowcf 1.0_

T2m (29.03.10). Experiments

-4

-2

0

2

4

6

8

10

12

0 ч 12 ч 0 ч 12 ч 0 ч 12 ч 0 ч

29 марта 29 марта 30 марта 30 марта 31 марта 31 марта 1 апреля

0С

станция

cf=0.05, T>=-0.2C при cf=0.1

cf=0.015

Smolensk

-8-6-4-202468

1012

0 ч 12 ч 0 ч 12 ч 0 ч 12 ч 0 ч


0С

станция

cf=0.05, T>=-0.2C при cf=0.1

cf=0.015

Kursk

-12-10

-8-6-4-202468

101214

0 ч 12 ч 0 ч 12 ч 0 ч 12 ч 0 ч


0С

станция

cf=0.05, T>=-0.2C при cf=0.1

cf=0.015

Kaluga

Snow fractional cover. Experiments

If hsnow>0.3m then cf_snow=0.01m

region

date

december january february

10 20 31 5 10 15 20 25 31 5 10 15 20 25 28

north 170 197 199 201 196 196

centre 137 198 197 209 210 217 230 240 244 251

south 105 136 184 195 229 308

Snow density for field, kg/m3

region

date

december january february

10 20 31 5 10 15 20 25 31 5 10 15 20 25 28

north 193 178 193 197 203 195

centre 85 158 195 251 188 214 216 249 248

Snow characteristics: snow density (1.12.09-28.02.10)

Snow density for forest

Conclusions• - SWE Forecasts are considerably overestimated by two versions of model COSMO-Ru. The cause is an

inaccuracy of SWE initial data, though snow depth initial data is quite correct. Needed: correction of the forming algorithm of SWE initial data using improved values of snow density

• - Snow density varies during the period of snow cover existing in time scale and in each region (from north to south). It also have some differences between field and forest.

So SWE calculation may take into consideration regional features of snow density. • - During snow accumulation period New snow scheme tends to overestimate snow depth after snowfalls.

So, in New snow scheme Recommendation: to do the correction of the computing algorithm of fresh snow density in New

scheme

• - During snow melting period New snow scheme reproduce more realistically: - time dependence of SWE; - T2m at night (due to using New snow scheme there is the improvement of T2m forecast by 1,5-2 C). It is connected with New snow scheme’s description of freezing daily melted water and following release

of heat.

• - During snow melting period the biggest mistakes of T2m forecasts were in vast regions for two versions (till 10 C), connected with equating to 0 C surface temperature of cell with snow.

• - Modifications with the snow fractional cover algorithm allowed to reduce the region area with mistaken temperature.

Recommendation: to improve the algorithm of taking into account surfaces without snow during snow melting periods.

Thank you for your attention!COLOBOC Workshop. Moscow, 6 September 2010

Snow parametrisations in COSMO-RU: analysis of winter-spring forecasts 2009-2010 COLOBOC Workshop....

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