p rogress of creating future wind speed forcing for vic runs xiaodong

1

Progress of creating future wind speed forcing for VIC runs

Xiaodong

Oct 1, 2013

2

1. Project Background

Assessment of the Vulnerability of Permafrost Carbon to Climate Change: A Sensitivity Analysis among Models

PI: Dave McGuire

Question:How would the carbon components in high-latitude permafrost change under the future climate change?

3


1. Simulate the historical and behavior of high-latitude permafrost area around the Arctic basin

Work flowClimate Forcings

(dependent on model

group choice)

Historical sim

1960-2006 required)

Detrended Forcings(de_temp de_co2 de_temp.de_prec)

Control runs1960-2006 required)

Results(hydrology components,

carbon cycle components)

4


2. Investigate the sensitivity of carbon cycle components toward future climate change (prec, temp, [co2])

Work flowClimate Forcings(CIMAP 5 scenarios,From Dave Lawrence)

Model Operation

2007-2299 required

Results(hydrology

components,carbon cycle components)

RCP4.5 and RCP8.5 scenarios, anomaly-correction strategy

Variables provided:1) Precipitation scale factors2) SurfT anomalies3) Wind (u & v) anomalies

4) Wind (combined) anomalies

VIC forcing:PrecipitationAir temperatureWind speed (combined)

5

2. Forcing Issues

1. Info about how to use future forcing anomalies

(From Dave Lawrence)1) Wind (combined) anomalies

2) To create future wind forcings

anomaly = future proj. - historical reference

¿t: timestep (in our case it is day)yobs: loop over 1996-2005

m: month (loop over 1-12)y: year (loop over 2006-2299) • One value for each month

• From 1996-2005 climatology run of CCSM4 historical simulation (case name: b40.20th.track1.1deg.008)

6

2. Negative future wind speed

2. Forcing Issues

7

2. Forcing Issues

Components of this negative future wind speed

8

3. Progress

2. Forcing Issues

Info about 2 types of forcing Dave’s forcing is from CCSM future runs (case name: b40.rcp4_5.1deg.001 and

b40.crp4_5.2300.001 and b40.20th.track1.1deg.008)

Our VIC forcing is from NCEP-NCAR reanalysis (Kalnay et al. 1996)

• Lowest level of model output (in geopontential height), so lowest layer is about 35m

• 1985-2004 Jan. average wind speed is 4.99m/s (cell 5895, at W.Siberia)

• Fixed at 10m height

• 1996-2005 Jan. average wind speed is 3.09m/s (cell 5895)

9

3. Progress

2. Forcing Issues

Scaling the wind speed down to 10m Surface roughness and displacement data is obtained from dataset for Stehekin River basin

(same as Ted’s setting in the West Siberia run)

¿Zd is displacement height(in m)Z0 is roughness (in m)

Averaged ratio for whole domain is:2.3452 (excludes water bodies and bare soil)3.2804 (take water bodies and bare soil as max. roughness and displacement veg type on land)

10

2. Forcing Issues

Scaling the wind speed down to 10m Surface roughness and displacement data is obtained from dataset for Stehekin River basin

(same as Ted’s setting in the West Siberia run)



3. Progress

11

2. Forcing Issues

Scaling the wind speed down to 10m



3. Progress

Choice Roughness(m)

Displacement(m) Ratio

1. Exclude water bodies and bare soil 0.4361 2.11 2.3452

2. Includes both 0.8430 2.90 3.2804

For each cell:Total roughness and displacement is calculated based on the area fraction of each vegetation type. The total sum is then rescaled by total fraction. Ratio is calculated separately for each cell. For choice 1, total fraction=1-(wetfrac*water_frac)-(dryfrac*baresoil_frac);For choice 2, total fraction=1

12

2. Forcing Issues

3. ProgressFor this grid cell, the future wind speed looks fine. But for some cells there are still occasional negative wind speed.

13

2. Forcing Issues

Further: Set min_wnd = 0.1m/s to complete avoid non-positive wind speed 0.1m/s is taken from VIC global parameter file

For Dennis: Do you approve this further limiting?

3. Progress

14

Progress of methane (CH4) observation project

Xiaodong

Oct 1, 2013

15


Tower Assimilation of CH4 observation in West Siberia

Target: Simulate the atmos [CH4] at towers in West Siberia wetland area.

Working with Dr. Shamil Maksyutov at NIES

16

2. Progress

Find out if there is any relationship between seasonal maximum [CH4] and ground water table depth and soil temperature

1. Feedback from last meeting

For 3 of 4 stations, there is relation between them, but for minimum [CH4].For 3 of 4 stations, there is relation between monthly avg [CH4] and monthly zwt, Tsurf, NPP , and wind stats.

IGR station (see map below) is far away from main wetland area, so the relationship here is a little different. I excluded this station from my regressions below.

17

2. Progress

2. Station info

Site Lat(N) Lon(E) Available Obs Start_year

Available ObsEnd_year

DEM 59.7914 70.8711 2005 2006

IGR 63.1903 64.4156 2005 2006

NOY 63.4292 75.78 2005 2006

KRS 58.1956 82.4244 2004 2006

18

2. Progress

3. Relation for seasonal averaged [CH4]

Stationavg_jja_[ch4]

(ppb)zwt_max

(m)Tsurf_avg

(C)Regressed

(ppb)

DEM 1985.553 -4.8244 17.2269 1975.185DEM 1964.68 -4.1642 16.90316 1973.067NOY 2006.91 -1.2875 18.17822 2006.065KRS 1989.838 -5.4552 18.50241 1992.4KRS 1974 -8.3458 18.17668 1974.265

For JJA (summer high emission period):

[𝐶𝐻 4 ]=4.5×𝑍𝑊𝑇 _ max+15.72 ×𝑇𝑠𝑢𝑟𝑓 +1726R^2 0.82

Adjusted R^2 0.64

Significance F 0.18Issues:Limited data points

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 20101950

1960

1970

1980

1990

2000

2010

f(x) = 0.999990593456135 x

Evaluation fo regression

Obs JJA avg [CH4] (ppb)

Regr

esse

d JJ

A av

g [C

H4]

(pp

b)

ZWT is always negative, same for the following regression.

19

2. Progress

4. Relation for seasonal minimum [CH4]

For JJA (summer high emission period):

[𝐶𝐻 4]min=4.5 ×𝑍𝑊𝑇 _ max+15.72 ×𝑇𝑠𝑢𝑟𝑓 +1726

R^2 0.82

Adjusted R^2 0.64

Significance F 0.18

Issues: Limited data pointsSolution: Try monthly analysis

Station min_jja_[ch4](ppb)

Tsurf_min(C)

zwt_min(m)

Regressed(ppb)

DEM 1867 10.0377 -20.2549 1866.277

DEM 1870 9.793 -12.3454 1865.767

NOY 1848 6.498 -4.9597 1848.698

KRS 1865 10.4424 -13.5917 1869.152

KRS 1849 7.7309 -65.797 1849.107

1845 1850 1855 1860 1865 1870 18751835

1840

1845

1850

1855

1860

1865

1870

1875

f(x) = 0.9999979078001 x

Evaluation fo regression

Obs JJA min [CH4] (ppb)Re

gres

sed

JJA

min

[CH

4] (

ppb)

20

2. Progress

5. Relation for summer monthly average [CH4] R^2 0.93

Adjusted R^2 0.63

Significance F 0.26

1920 1940 1960 1980 2000 2020 20401880

1900

1920

1940

1960

1980

2000

2020

2040

f(x) = 0.999981217774094 x

Summer months, excludes NPP_min

Obs [ch4] (ppb)

Regr

esse

d [c

h4]

(ppb

)

11 data points from summer months (June, July, August).Not JJA average. Use ZWT, Tsurf, NPP stats for regression

[𝐶𝐻 4 ]=1765+160ZWT −99 ZWT _ max −69ZWT _ min +100𝑇𝑠𝑢𝑟𝑓 −25Tsurf _ max −82 Tsurf _ min +276𝑁𝑃𝑃 −184NPP _ max¿

Term Relation

ZWT --- avg +

ZWT --- max -

ZWT --- min -

Tsurf --- avg +

Tsurf --- max -

Tsurf --- min -

NPP --- avg +

NPP --- max -

21

2. Progress

5. Relation for summer monthly average [CH4]

1920 1940 1960 1980 2000 2020 2040188019001920194019601980200020202040

f(x) = 0.999981217774094 x

Summer months, excludes NPP_min

Obs [ch4] (ppb)

Regr

esse

d [c

h4]

(ppb

)

Possible application:

• Available fro VIC :1948-2006 historical zwt, Tsurf and NPP simulation results

• Use: Regression relationship• Produce: 1948-2006 historical [CH4] concentration. See if the

trend is correct.


22

2. Progress

6. Relation for summer monthly average [CH4]


0 20 40 60 80 100 120 140 1601000

1200

1400

1600

1800

2000

2200

2400

2600

f(x) = 0.358566478103963 x + 1869.06640951548

Regressed historical [CH4] at DEM station

Month , only JJA siince 1948

Regr

esse

d [C

H4]

(pp

b)

0 20 40 60 80 100 120 140 1601000

1200

1400

1600

1800

2000

2200

2400

2600

2800

f(x) = − 0.232646378191324 x + 2029.84659636589

Regressed historical [CH4] at NOY station

Month, only JJA since 1948

Regr

esse

d [C

H4]

(pp

b)

Possible Solution: Involve wind speed ?

DEM shows increasing trend (0.3586), as expected NOY shows decreasing trend (-0.2326), unexpected

23

2. Progress

5. Relation for all the available monthly average [CH4] R^2 0.55

Adjusted R^2 0.47

Significance F 0.00012739 data points.Use ZWT, Tsurf, NPP and wnd_speed stats for regression

Term Coefficient

Intercept 1921.39

ZWT min (m) 1.199391

Tsurf avg (C) -16.3283

Tsurf max (C) 6.440634

Tsurf min (C) 5.205514

NPP avg (gC/m2/day) 83.6884

Wnd min (m/s) 31.320241850 1900 1950 2000 2050 2100

1850

1900

1950

2000

2050

2100

f(x) = 0.999708076271485 x

Comparison of all usable monthly avg [CH4]

Obs [CH4] (ppb)Re

gres

sed

[CH

4]

(ppb

)

24

2. Progress

5. Relation for all the available monthly average [CH4]

Reconstruction of historical atmos [CH4] at DEM station

1/1/1948 9/9/1961 5/19/1975 1/25/1989 10/4/20021900

2000

2100

2200

2300

2400

f(x) = 0.00057262203341112 x + 2014.45231701353

Regressed historical [CH4] at DEM station, at 45 m

Month

atm

os [C

H4]

(p

pb)

There is increasing trend (0.0006ppm/month) in this reconstructed series.

25

2. Progress


Reconstruction of historical atmos [CH4] at NOY station

1/1/1948 9/9/1961 5/19/1975 1/25/1989 10/4/20021900

2000

2100

2200

2300

f(x) = 0.000511144782529114 x + 2000.09269936995

Regressed historical [CH4] at NOY station, at 21m

Month

atm

os [C

H4]

(p

pb)

26

2. Progress


Reconstruction of historical atmos [CH4] at KRS station

1/1/1948 9/9/1961 5/19/1975 1/25/1989 10/4/20021800

1900

2000

2100

2200

2300

2400

f(x) = 0.000151384218189652 x + 2032.66499244131

Regressed historical [CH4] at KRS station, at 35m

Month

atm

os [C

H4]

(p

pb)

27

2. Progress

6. Conclusion

At stations DEM, NOY and KRS, atmosphere [CH4] observation at the lowest level (differ for each station) shows significant relationship (sig.F=0.000127<0.05) with CH4 emission rate and 10m wind speed.

CH4 emission rate is controlled by ground water table depth (zwt), surface soil temperature (Tsurf) and NPP.

Atmos [CH4] can be approximated by zwt, Tsurf, NPP and wnd statistics. This approximation might be used to reconstruct the historicsl atmosphere [CH4] at these 3

stations. The reconstructed atmos [CH4] shows an increasing trend at all 3 stations. My current question

is: The trend is correct, but what about the values (+0.0004ppb/month)?

p rogress of creating future wind speed forcing for vic runs xiaodong

Documents