Evidence of Regional Warming during the 20th Century in Alpine
and Subalpine Lakes in the Western United States
David F. Porinchu
Department of Geography
The Ohio State University
Funding provided by The National Science
Foundation: Geography and Regional Sciences
and Paleoclimate
Stella Lake, Great Basin N. P.
August, 2005
Co-Authors and Collaborators:
Scott Reinemann, Jason Box, Bryan Mark, Nicolas Rolland : Geography, OSU
Aaron Potito: Geography, National University Ireland
Katrina Moser: Geography, University of Western Ontario
Jeff Munroe: Geology, Middlebury College
Amy Bloom: Geology-Geography, Illinois State University
Glen MacDonald: Geography and OBEE, UCLA
Dicrotendipes
Heterotrissocladius
Porinchu and MacDonald, 2003
Calibration Set Development
Eastern Sierra
Nevada
Uinta
Mountains
Munroe and Mickleson (2002)
PRISM Group, Oregon State University
(http://prism.oregonstate.edu/)
Porinchu et al. (2007b)
PRISM Group
Oregon State University
Surface Water Temperature Inference Model
Observed Surface Water Temperature (oC)
22
r2jack= 0.66
RMSEP = 1.4oC
N = 90
20
18
16
14
Average July Air Temperature Inference Model
12
10
Porinchu et al. 2007b
8
8
10
12
14
16
18
o
Inferred Surface Water Temperature ( C)
20
22
Inferred Average July Air Temperature (oC)
15
r2 jack= 0.55
RMSEP = 1.0oC
n = 81
14
13
12
11
10
9
9
10
11
12
13
14
Observed Average July Air Temperature (oC)
Based on data available from the PRISM Group,
Oregon State University
(http://prism.oregonstate.edu/)
15
Application of Surface Water Temperature Inference Model
Eastern Sierra
Nevada
MG-2
Moat Lake
Rocky
Bottom Lake
Porinchu et al., 2007a
Year
1920
1900
1880
1860
Depth (cm)
1980
2
1960
3
0
ol
iv
er
i
Dicrotendipes
20
40
ty
pe
(1
3.
Sy
9)
no
r
He tho
te cla
ro diu
tri
ss s (1
oc
He
3
la .9)
te
di
ro
us
Cr tris
m
ico so
ar
ci
to cla
du
Di pu
d
i
s
cr
u
ty
ot s/O s g
pe
en rth
rim
di
o
(1
pe cla sh
4.
0)
di aw
s
us
(1
it
5.
y
6) (14 pe
Co
.5
ry
) (14.
no
3)
ce
ra
nr
.a
m
bi
Ps
gu
ec
a
tro
(1
5.
cla
6)
d
Ch
iu
s
iro
se
n
m
Ta om
i/s
ny us
or
ta
di
(
1
r
Pr
4
(1
s
5.
oc us .9)
2)
in
la
d
di
us ete
(1 rm
5.
i
3) nab
le
(1
5.
Pe
2)
nt
a
Ta neu
ny rin
i
ta
rs (Ot
us
h
Ta
ty er)
p
ny
e (15
ta
C
.3
Ta rsu
)
ny s
ta typ
rs
us e E
Za
ty
pe
lu
ts
H
c
He hi
a
ad
Co
ry
no
ce
ra
Cool Water Taxa
60 0 10 0
20 0 10 0 10 0
20
40 0
Temperate Taxa
20
40 0
20 0 10 0 10 0
R e l a t i ve A b u n d a n c e
20
40
Moat Lake
0
2000
1
1940
4
5
6
7
8
9
10
0
0
20 0 10 0
20 0 10 0
20
Mean SWT = 15.4oC
0.0
1
1900
1920
1940
1960
1980
2000
1940
1960
1980
2000
Rocky Bottom
Mean SWT = 13.8oC
0
-1
1900
1920
1
Mean SWT = 15.6oC
Moat Lake
Deviation from mean temperature (ºC)
-0.5
0
RECONSTRUCTED LAKE TEMPERATURES
McGee Lake
0.5
-1
1920
1940
1960
1980
2000
1900
1920
1940
1960
1980
2000
Fresno, CA
Summer
Temperatures
1900
2
0
-2
year AD
Porinchu et al., 2007a
Application of July Air Temperature Inference Model
Snake
Snake
Range
Range
Uinta
Mountains
Vernal, UT
NV, Climate Division 2
Summary
„
„
„
Midge communities in the Sierra Nevada, Uinta Mountains and
Snake Range are sensitive to fluctuations in summer surface
water temperature and air temperature
Significant changes in midge community composition during the
late 20th century likely reflect the influence of increasing
summer temperatures in the Great Basin
Chironomid analysis may be able to provide high-resolution
(sub-decadal to sub-centennial) paleoclimate reconstructions of
regional climate change (LIA, MCO, Younger Dryas)