Fog in the California Redwood forest: Ecosystem inputs and use by plants T.E. Dawson.
Summer fog variability in the coast redwood region: climatic relevance and ecological implications...
-
date post
20-Jan-2016 -
Category
Documents
-
view
219 -
download
0
Transcript of Summer fog variability in the coast redwood region: climatic relevance and ecological implications...
![Page 1: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/1.jpg)
Summer fog variability in the coast redwood region: climatic relevance and ecological implications
James A. Johnstone
Department of Environmental Science, Policy, & ManagementUniversity of California, Berkeley
![Page 2: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/2.jpg)
Coast Redwood
Sequoia sempervirens (D. Don)
Modern distribution suggests a dependence on marine conditions / coastal fog
![Page 3: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/3.jpg)
Research Questions:
How and why does summer fog in the redwood region vary on annual to multi-decadal time scales?
How is its variability connected to marine conditions and regional climate patterns (e.g. ENSO, PDO)?
How have these conditions changed over the past century?
Impacts on redwood function / ecology?
![Page 4: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/4.jpg)
???
![Page 5: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/5.jpg)
Arcata 1951-2008
Monterey 1951-2008
Primary data:
Hourly airport readings of cloud ceiling height
June-September summers
Near-continuous records (1951-2008) in the Redwood region
Fog = cloud ceiling at/below 400 m
Sonoma 2003
![Page 6: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/6.jpg)
Hourly cloud heightSonoma County Airport
June 2003
![Page 7: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/7.jpg)
Hourly cloud heightSonoma County Airport
Coast Redwood Forest 300m elev. Sonoma County
June 2003
![Page 8: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/8.jpg)
Hourly cloud heightSonoma County Airport
Coast Redwood Forest 300m elev. Sonoma County
June 2003
Fog raises humidity, controls water loss by Redwoods.
![Page 9: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/9.jpg)
Summer Climate of the NE Pacific
Key elements:
North Pacific High
Alongshore winds
Coastal upwelling
Coastal stratus/fog
![Page 10: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/10.jpg)
Coastal temperature inversion,
vertical humidity contrast
Mean summer profiles at Oakland:
400 m
Relative Humidity Temperature
![Page 11: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/11.jpg)
Summer Daily Maximum Temperatures: Northern California
Inland-coast TMAX contrast
Data: PRISM (Oregon State U.)Daly et al. 2004
![Page 12: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/12.jpg)
Summer Daily Maximum Temperatures: Northern California
Capping inversion restricts marine layer to coastal elevations below ~ 400m
![Page 13: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/13.jpg)
Summer mean fog frequency
Redwood distribution ~ 30% coastal fog threshold
![Page 14: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/14.jpg)
Diurnal cycle of ceiling height
clear sky
![Page 15: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/15.jpg)
![Page 16: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/16.jpg)
![Page 17: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/17.jpg)
Interannual fog variability 1951-2008
Varies by a factor of 2.3
![Page 18: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/18.jpg)
Extreme years:
1951 (14.8 hrs)
13 fog-free days (daytime hrs)
1997 (6.4 hrs)
62 fog-free days
Hours of Fog per day
![Page 19: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/19.jpg)
Extreme years:
1951 (14.8 hrs)
13 fog-free days (daytime hrs)
1997 (6.4 hrs)
62 fog-free days
2009 near-average(~10 hrs)
Hours of Fog per day
![Page 20: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/20.jpg)
Palo Alto Airport
![Page 21: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/21.jpg)
Fog enhanced with NE-ward expansion of N Pacific High
![Page 22: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/22.jpg)
Fog correlations with sea-level pressure (SLP)
r = 0.58
![Page 23: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/23.jpg)
Fog vs. Oregon coast meridional wind speed (r = -0.69)
![Page 24: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/24.jpg)
Fog correlations with sea surface temperature (SST)
PDO-type SST signature
Summer Fog-PDO correlation
r = -0.52
![Page 25: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/25.jpg)
Fog correlations with summer land TMAX
Coherent pattern over the entire U.S. west coast
![Page 26: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/26.jpg)
Fog correlations with upper-air temperatures at Oakland
500 m
![Page 27: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/27.jpg)
Fog vs. Oakland Inversion Strength
(r = 0.67) T1000-2000 – T0-400
![Page 28: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/28.jpg)
Inversion strength correlations with TMAX
![Page 29: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/29.jpg)
Vertical and longitudinal temperature variations related:
Weak inversion permits marine air and cloud to rise and penetrate to interior
Subsidence tends to warm the interior and intensify the coastal inversion
![Page 30: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/30.jpg)
Strong coupling among:
Inland-coast TMAX contrast
Inversion strength
Fog frequency Cross-correlations: 0.65-0.85
![Page 31: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/31.jpg)
TMAX Inland-Coast Contrast 1901-2008
Fog correlation: r = 0.84
Suggests ~33% reduction in inversion strength and fog frequency.
![Page 32: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/32.jpg)
Ukiah(interior)
Berkeley(marine)
Change in TMAX contrastexemplified by Ukiah-minus-Berkeley difference.
1901-1925: 9.6°C difference
1951-2008: 6.3°C difference
50% reduction
![Page 33: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/33.jpg)
TMAX Contrast, Northern California SST 1900-2008r = -0.73
![Page 34: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/34.jpg)
Conclusions:
20th century weakening of TMAX contrast implies:
Greater inland penetration of marine air in summer
Weakened inversion
Reduced fog frequency
Important terrestrial climate changes linked to ocean-atmosphere variability along the U.S. West coast and the broader N. Pacific.
Greater evaporative demands may have important implications for coastal terrestial species and ecosystems, including redwood
(heightened drought sensitivity?)
![Page 35: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/35.jpg)
Further work:
Stable isotope tree-ring calibration:
4 Redwood sites:
~50-yr analysis of
δ18O, ∆13C (discrimination)
![Page 36: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/36.jpg)
∆13C: Expected positive relationship with humidity / fog
Positively correlated with:
Summer fog frequency
![Page 37: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/37.jpg)
∆13C: Expected positive relationship with humidity / fog
Negatively correlated with:
Coastal SST
PDO
![Page 38: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/38.jpg)
δ18O correlated with sprintime pressure over the California coast
and much of the globe
(Multiple local factors appear to be involved)
![Page 39: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/39.jpg)
Research funded in part by:
The Save-the-Redwoods League
The Berkeley Atmospheric Sciences Center
The National Science Foundation
Thanks to collaborators:
Todd Dawson (Berkeley)
John Roden (Southern Oregon Univ.)
![Page 40: Summer fog variability in the coast redwood region: climatic relevance and ecological implications James A. Johnstone Department of Environmental Science,](https://reader036.fdocuments.us/reader036/viewer/2022062322/56649d4b5503460f94a28a42/html5/thumbnails/40.jpg)