A Range-Wide Model of NightTime Temperature Inversion
Based on Hourly Temperature
Data
Christopher Van de Ven1, Stuart B. Weiss2,
and Gary Ernst3
1 = Albion College, 2 = Creekside Center for Earth Observation,
3 = Stanford University
Treeline Response to Climate
Change
Peters and Darling, 1985.
Upslope Migration
Millar, Westfall, Delany, 2007
Shift of Aspect
Downslope Migration
Millar, Westfall, Delany, 2007
Downslope Migration
1947
2005
Pines in 2005, not in 1947
iButton Placement
•Within 6” lengths of white PVC
•Placed on ground
•Openings oriented N/S
•Record hourly temperature
•Late July – early Oct.
iButtons
•2006: 35 under sagebrush
• Around Crooked Creek
•2007: 70 total
• At CC, Campito Mtn, and Mt.
Barcroft
•2008: 98 total (+20 in transects)
• CC, Campito Mtn., and Mt.
Barcroft
Distribution of iButtons
2006 Distribution of Sensors
10/03/2006 11:51
09/30/2006 11:51
09/27/2006 11:51
09/24/2006 11:51
09/21/2006 11:51
09/18/2006 11:51
09/15/2006 11:51
09/12/2006 11:51
09/09/2006 11:51
09/06/2006 11:51
09/03/2006 11:51
08/31/2006 11:51
08/28/2006 11:51
08/25/2006 11:51
08/22/2006 11:51
08/19/2006 11:51
08/16/2006 11:51
08/13/2006 11:51
08/10/2006 11:51
08/07/2006 11:51
08/04/2006 11:51
08/01/2006 11:51
07/29/2006 11:51
07/26/2006 11:51
07/23/2006 11:51
Temperature (°C)
All Data for 5 Stations
40
30
20
10
0
-10
-20
-10
Date
8/29/06 12:51
8/29/06 0:51
8/28/06 12:51
8/28/06 0:51
Stn21: E. Ridge
Stn4: N. Ridge
8/27/06 12:51
8/27/06 0:51
8/26/06 12:51
8/26/06 0:51
Stn28: Valley
Stn20: W. Ridge
8/25/06 12:51
8/25/06 0:51
8/24/06 12:51
8/24/06 0:51
8/23/06 12:51
-5
8/23/06 0:51
8/22/06 12:51
8/22/06 0:51
Temperature (°C)
Data for 5 Stations
35
30
25
20
15
10
5
0
Stn15: S. Ridge
Hourly Avg. Temperature
25.0
Stn15: S. Ridge
Temperature (°C)
20.0
15.0
Stn20: W. Ridge
Stn21: E. Ridge
Stn28: Valley
Stn4: N. Ridge
10.0
5.0
0.0
‐5.0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Hour
Average Hourly Temperature
All Sites
Crooked Creek All Stations
Average Hourly Temperature July 23- Oct 6 2006
30
25
degC
20
15
10
5
0
-5
0
6
12
Hour
18
24
Mean Minimum Temperature vs.
Elevation
Mean Minimum Temperature July 23-Oct 6 2006
Crooked Creek
6
5
Temperature
degC (° C)
4
3
2
1
0
-1
-2
-3
-4
3080
3100
3120
3140
3160
Elevation (meters)
3180
3200
3220
Minimum Temperature Model
• Temperature dependent on
– Elevation
• Higher = colder
– Topographic position
• Valleys get cold air drainage
• Ridges/Peaks are more exposed
Topographic Position
TPI = Elevation – Mean elev. (500m radius)
A. Weiss
Creating the Temperature Model:
Crooked Creek Valley
• Multiple least-squares regression
– Average minimum temp. July 23 – Oct. 6
• Best fit
– Topographic position (500m radius)
– Slope
– Absolute value of topographic position
• R2=0.92
AbsTPI: 0 (blue) to +93 (red)
TPI: -62 (blue) to +99 (red)
Slope: 0º (Blue) to 40º (Red)
Weather Station Data
y = -0.0059x + 20.213
R2 = 0.9898
Avg. Annual Temp (ºC)
Lapse Rate
16
14
12
10
8
6
4
2
0
-2
-4
1000
Bishop; 1252m
Dyer; 1516m
Barcroft
3801m
Crooked Creek
3094m
1500
2000
2500
3000
3500
Elevation (m)
White Mtn. 1 = Crooked Creek
White Mtn. 2 = Barcroft
4000
1947 at Crooked Creek
Cold-Air Drainage
South-facing
North-facing
2005 at Crooked Creek
Cold-Air Drainage with Warmer Air
Temperature
South-Facing
North-Facing
Pairs – In Open / Under Sage
08/10/2007 00:58 08/10/2007 12:58 08/11/2007 00:58 08/11/2007 12:58 08/12/2007 00:58 08/12/2007 12:58 08/13/2007 00:58 08/13/2007 12:58 08/14/2007 00:58 08/14/2007 12:58 08/15/2007 00:58 08/15/2007 12:58 08/16/2007 00:58 08/16/2007 12:58 08/17/2007 00:58 08/17/2007 12:58 08/18/2007 00:58 08/18/2007 12:58 08/19/2007 00:58 08/19/2007 12:58 08/20/2007 00:58 08/20/2007 12:58 Temp Differences (degC)
Comparing Under Sage & In Open
Stn32‐Sage
Stn33‐Open
45
40
35
30
25
20
15
10
5
0
‐5
‐10
Open-Sagebrush Comparison
08/10/2007 00:58 08/10/2007 12:58 08/11/2007 00:58 08/11/2007 12:58 08/12/2007 00:58 08/12/2007 12:58 08/13/2007 00:58 08/13/2007 12:58 08/14/2007 00:58 08/14/2007 12:58 08/15/2007 00:58 08/15/2007 12:58 08/16/2007 00:58 08/16/2007 12:58 08/17/2007 00:58 08/17/2007 12:58 08/18/2007 00:58 08/18/2007 12:58 08/19/2007 00:58 08/19/2007 12:58 08/20/2007 00:58 08/20/2007 12:58 Temp Differences (degC)
Comparing Meadow and Woodland
Stn28: Woodland
Stn27: Meadow
35
30
25
20
15
10
5
0
08/10/2007 00:58 08/10/2007 12:58 08/11/2007 00:58 08/11/2007 12:58 08/12/2007 00:58 08/12/2007 12:58 08/13/2007 00:58 08/13/2007 12:58 08/14/2007 00:58 08/14/2007 12:58 08/15/2007 00:58 08/15/2007 12:58 08/16/2007 00:58 08/16/2007 12:58 08/17/2007 00:58 08/17/2007 12:58 08/18/2007 00:58 08/18/2007 12:58 08/19/2007 00:58 08/19/2007 12:58 08/20/2007 00:58 08/20/2007 12:58 Temp Differences (degC)
Comparing Meadow and Woodland
27‐28: Mdw‐Woods
8
6
4
2
0
‐2
‐4
‐6
‐8
Thank You!
• Funding from Albion College FDC grants and
Blanchard fellowship, and from Stanford
University
• Stanford-Albion Geobotanical Survey
– Lisa Colville
– Paul Gehres
– Brittany Myers
•
•
•
•
– White Mountain Groupies
– Jimmy Spaulding
– Christal Niederer
White Mtn. Research Station (UC)
Connie Millar and Bob Westfall (SNRC, USDA FS)
Adelia Barber (UCSC)
Linah Abaneh (William & Mary) and Wally
Woolfenden (USFS)