effect of landscape change on climate and weather · 223.5 wm 22-107.0 wm22 75.0 wm22 147.0 wm2...

Effect of Landscape Effect of Landscape Change on Climate Change on Climate

and Weatherand WeatherRoger A. Pielke Sr. and Adriana Beltrán-Przekurat

Department of Atmospheric ScienceColorado State University

Long-Term Ecological Research Program, New Mexico State University, Las Cruces, NM

October 29th, 2004

Regional LandRegional Land--Use Change Use Change Effects on Climate in the Effects on Climate in the

SummerSummerMarshall, C.H. Jr., R.A. Pielke Sr., L.T. Steyaert, and D.A. WilMarshall, C.H. Jr., R.A. Pielke Sr., L.T. Steyaert, and D.A. Willard, 2004: lard, 2004: The impact of anthropogenic land cover change on warm season senThe impact of anthropogenic land cover change on warm season sensible sible weather and seaweather and sea--breeze convection over the Florida peninsula. breeze convection over the Florida peninsula. Mon. Wea Mon. Wea RevRev., 132, 28., 132, 28--52. 52.

http://blue.atmos.colostate.edu/publications/pdf/Rhttp://blue.atmos.colostate.edu/publications/pdf/R--272.pdf272.pdf

Max and Min Temp Trends

Two-month average of the surface latent heat flux (W m-2) from the model simulations of July and August 1994 with pre-1900s land cover (top), 1994 land use (middle), and the difference field for the two (bottom; 1994 minus pre-1900s case).

Regional LandRegional Land--Use Change Use Change Effects on Climate in the Effects on Climate in the

WinterWinter

Marshall, C.H. Jr., R.A. Pielke Sr., and L.T. Steyaert, 2003: CMarshall, C.H. Jr., R.A. Pielke Sr., and L.T. Steyaert, 2003: Crop rop freezes and landfreezes and land--use change. use change. NatureNature, 426, 29, 426, 29--30. 30.


Marshall, C.H., R.A. Pielke Sr., and L.T. Steyaert, 2004: Has thMarshall, C.H., R.A. Pielke Sr., and L.T. Steyaert, 2004: Has the conversion of e conversion of natural wetlands to agricultural land increased the incidence annatural wetlands to agricultural land increased the incidence and severity of d severity of damaging freezes in south Florida? damaging freezes in south Florida? Mon. Wea. RevMon. Wea. Rev., in press.., in press.


1997

Min T

1997

duration

Pielke, R.A., T.J. Lee, J.H. Copeland, J.L. Eastman, C.L. Pielke, R.A., T.J. Lee, J.H. Copeland, J.L. Eastman, C.L. Ziegler, and C.A. Finley, 1997: Use of USGSZiegler, and C.A. Finley, 1997: Use of USGS--provided provided data to improve weather and climate simulations. data to improve weather and climate simulations. Ecological Applications, 7, 3Ecological Applications, 7, 3--21.21.

Landscape Change Landscape Change In the Great PlainsIn the Great Plains

Model output cloud and water vapor mixing ratio fields at 21 GMT on 15 May 1991. The

clouds are depicted by white surfaces with qc = 0.01 g/kg, with

the sun illuminating the clouds from the west. The vapor mixing ratio in the planetary boundary layer is depicted by the green

surface with qv = 8 g/kg. The tan surface is the ground. Areas formed by the intersection of clouds or the vapor field with

lateral boundaries are flat surfaces, and visible ground

implies qv < 8 g/kg. The vertical axis is height, and the blue

backplanes are the north and east sides of the grid domain.

Model terrain (m above mean sea level and grid configuration

for the 15 May 1991 dryline simulations. The outer

dimensions of the figure denote the outermost grid, while nested

grids of increasing resolution are also indicated.

USGS land-cover data (color-filled pixels) and topography (contours) used in the 15

May 1991 dryline simulation (r-km increment). The predominant USGS land

cover class has been converted to a BATS classification (Dickinson et al. 1986). From

top to bottom the color bar depicts the following BATS categories (numerical value

of BATS category in parentheses): evergreen shrub (ES), irrigated crop (IC),

deciduous broadleaf tree (DBT), short grass (SG), crop/mixed farming (CMF), and other

miscellaneous land-cover types (other).

Has The Observed Landscape Has The Observed Landscape Change In The Jornada Change In The Jornada

Experimental Range Had A Experimental Range Had A Significant Effect On Surface Significant Effect On Surface

Sensible And Latent Heat Fluxes, Sensible And Latent Heat Fluxes, Air Temperature, And Relative Air Temperature, And Relative

Humidity?Humidity?

1915 1998

grass 37%shrub 63% shrub 92%

grass 8%

Gibbens, R. P. et al. 2004. Vegetation changes in the Jornada basin from 1858 to 1998. Journal of Arid Environments. In press.Peters and Gibbens in review

Change in vegetation types at the Jornada Experimental Range

(total area = 78,000 ha or 193,000 acres)

1858 1998

GRASS LARREAMESQUITE TARBUSH

GEMRAMS grid design

POOR

GRASS

Experimental Design

Two experiments were performed using two land cover scenarios (1858 and 1998) using identical initial meteorological conditions. These are the control cases.Three sensitivity experiments were performed using different initial soil moisture conditions, for both land cover scenarios, 1858 and 1998.

Dry case: the whole profile is 20% drier than the control case.Wet case: the first 1 m of the soil profile is 20% wetter than the control case, and the rest of the layers have the same soil moisture as the control case.Wetter case: same as wet case, but 40% wetter than the control case.

Different sets of experiments were performed using GEMRAMS, a coupled plant and atmospheric model.

Design of Numerical SimulationDesign of Numerical Simulation2 days:0500 LST May 23 – 0100 LST May 24, 20020500 LST September 3 – 0100 LST September 24, 2002Grid

50x50 grid, centered at 32°37’ N, 106°44’ W1x1km grid spacing

Initial meteorological dataMean sounding for the region using NCEP

reanalysisInitial soil moisture data

Typical May conditions, obtained from an average of 10 years of neutron probe measurements and some gravimetric data

0.1200.1200.0180.0180.3050.30515.015.00.3570.357““Poor grassPoor grass””

0.3320.3320.0500.0500.2900.29022.422.41.2051.205TarbushTarbush

0.4000.4000.0600.0600.2650.26523.423.41.1541.154LarreaLarrea

0.4000.4000.0600.0600.2700.27022.422.41.4291.429MesquiteMesquite

0.1200.1200.0180.0180.3050.30525.225.20.4960.496Grass (*)Grass (*)

Displacement Displacement height (m)height (m)

Roughness Roughness length (m)length (m)AlbedoAlbedoVegetation Vegetation

cover (%)cover (%)LAILAIVegetation typesVegetation types

Parameter values for each vegetation typeParameter values for each vegetation type

(*) For 1858 vegetation LAI and vegetation cover for Grass were 0.357 and 35% respectively.

Latent Heat FluxesLatent Heat FluxesSensible Heat FluxesSensible Heat Fluxes

18581858

19981998

1998 1998 -- 18581858

Diurnal meanDiurnal meanSeptember September

175.0 Wm175.0 Wm22

110.2 Wm110.2 Wm22

--64.0 Wm64.0 Wm22

46.5 Wm46.5 Wm22

101.9 Wm101.9 Wm22

55.4 Wm55.4 Wm22


18581858

19981998

1998 1998 -- 18581858

Diurnal meanDiurnal meanMay May

252.1 Wm252.1 Wm22

212.3 Wm212.3 Wm22

--39.0 Wm39.0 Wm22

55.3 Wm55.3 Wm22

89.7 Wm89.7 Wm22

34.3 Wm34.3 Wm22


18581858

19981998

1998 1998 -- 18581858

330.6 Wm330.6 Wm22

223.5 Wm223.5 Wm22

--107.0 Wm107.0 Wm22

75.0 Wm75.0 Wm22

147.0 Wm147.0 Wm22

72.0 Wm72.0 Wm22

September15:00 LST


18581858

19981998

1998 1998 -- 18581858

414.3 Wm414.3 Wm22

357.4 Wm357.4 Wm22

--56.9 Wm56.9 Wm22

81.3 Wm81.3 Wm22

119.6 Wm119.6 Wm22

38.3 Wm38.3 Wm22

May15:00 LST

Relative HumidityRelative HumidityTemperatureTemperature

18581858

19981998

1998 1998 -- 18581858

27.5 °C27.5 °C

27.0 °C27.0 °C

--0.5 °C0.5 °C

39.3 %39.3 %

41.5 %41.5 %

2.2%2.2%

September15:00 LST

Relative HumidityRelative HumidityTemperatureTemperature

18581858

19981998

1998 1998 -- 18581858

19.8 °C19.8 °C

19.7 °C19.7 °C

--0.15 °C0.15 °C

16.9 %16.9 %

17.4 %17.4 %

0.48 %0.48 %

May15:00 LST

Soil Moisture SensitivitySoil Moisture SensitivityLatent Heat FluxesLatent Heat FluxesSensible Heat FluxesSensible Heat Fluxes

19981998

229.2 Wm229.2 Wm22

5.7 Wm5.7 Wm22

141.2 Wm141.2 Wm22

--5.8 Wm5.8 Wm22

15:00 LST

DRY CASE

DRY - CONTROL


19981998

199.7 Wm199.7 Wm22

--23.8 Wm23.8 Wm22

185.6 Wm185.6 Wm22

38.7 Wm38.7 Wm22

15:00 LST

WET CASE

WET - CONTROL


19981998

202.7 Wm202.7 Wm22

--20.8 Wm20.8 Wm22

196.8 Wm196.8 Wm22

49.8 Wm49.8 Wm22

15:00 LST

WETTER CASE

WETTER - CONTROL

SummarySummaryDiurnally-averaged differences in the fluxes over the area

can be high, depending on daily atmospheric conditions. Important local differences in time and space were found.

Relative changes in surface fluxes from 1858 to 1998 are higher for latent heat.

Air temperature are influenced by surface fluxes, but simulated differences between the two vegetation distributions are not too high.

Relatively high sensitivity to soil moisture conditions, in particular for 1998 vegetation and for latent heat flux. The relative changes in the surface fluxes were lower than those forthe vegetation changes.

LAI differences seem to be the dominant parameter controlling the energy budget. Albedo is also important.

effect of landscape change on climate and weather · 223.5 wm 22-107.0 wm22 75.0 wm22 147.0 wm2...

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