Lake Spearman Correlation Slope Standard error
Erie 0.93 1.11 3.58 Huron 0.88 0.98 3.65 Michigan 0.92 0.99 3.13
Superior 0.87 1.20 3.70
Ludovicus P.H. (Rens) Van Beek1, Tessa Eikelboom2, Michelle T.H. Van Vliet3, and Marc F.P. Bierkens1,4
1 Utrecht University, 2 VU University Amsterdam, 3 Wageningen University, 4 Deltares (Netherlands: m.bierkens@geo.uu.nl)
Introduction
Modelling global fresh water temperature because:
• Water temperature influences physical, chemical and biological processes: ice formation, hydro-geochemistry, aquatic habitats.
• Rivers transport heat along the Earth’s drainage network: local effects v. regional effects.
Objectives
1. Develop a physically-based global surface freshwater temperature model;
2. Validate simulated surface freshwater temperatures against observations for different environmental settings.
Model setup
Incorporation of a physical-deterministic energy-balance model for surface freshwater in the global-scale hydrological model PCR-
GLOBWB.
Snow cover
QBf Canopy
Store 2 Store 1
Store 3
PREC Epot
Eact
QDR
P QSf
P T
River ice
Tw
TA RS
Snow/Rain QChannel
PREC Epot
QChannel
TA RS
Snow/Rain LH(Epot)
Q
Model structure of PCR-GLOBWB
Water energy balance model for a rectangular channel
A
) ( ) (x T x Q
Cp
w
) ] ) (
(
[ dx
x x QT QT Cp
w
As
dx
L H
wE S, , 1
m
w p s i s i
i
C q T
A
) ( ) (x T x Q
Cp
w
) ] ) (
(
[ dx
x x QT QT Cp
w
As
dx
L H
wE S, , 1
m
w p s i s i
i
C q T
, , 1
( ) ( )
(1 )
M
w p w p w w w p s i s i
i
hT vhT
C C S L L H E C q T
t x
dr a sf a bf a
w w a
p w M
i
i s i s p
w q T q T q T
f pT f
C T
q
C 1
1
,
,
Water Temperature
River ice formation
H H S L L
dt dz
i i
w
f 1 2 (1 )
23 32 32
2
i b
c
n
n n
n
i 0 . 0493 h
0.23z
i0.57
2 2
P h W P h W
Data and validation
Holdridge Life Zone Classification
Ocean Tundra Cold Parklands Forest Tundra
Boreal Forest Cool Desert Steppe Temperate Forest
Hot Desert Chapparal Warm Temperate Forest Tropical Semi-Arid
Tropical Dry Forest Tropical Seasonal Forest Tropical Rain Forest
Validation
Holdridge Life Zones
0.00 0.25 0.50 0.75 1.00 1.25
Tundra Cold Parklands
Forest Tundra Boreal Forest
Cool De ser
t Steppe
Tem perate Forest
Hot De sert Chapparal
Wa rm Temp
erate Forest Tropical Se mi-Ar
id
Tropical Dry Forest Tropical Se
asonal Forest Tropical Ra
in Forest
Correlation, Alpha [-]
0 5 10 15 20 25 30
T [°C]
Correlation Alpha Mean temperature
Alpha [-]
0 0.5 1 1.5 2 2.5 3
USGS/NOAA dayly data
Spearman correlation [-]
0 0.25 0.5 0.75 1
Arkansas abov e Pueblo
Arkansas John Martin
Arkansas L as Anima
s
Colorado Ca meo
Colorado Lee's Ferry Colorado Silver Colorado Utah Stateline
Delaware Trenton Green River
Campbells Jackso
n River
Potomac Washington DC San
Joaquin Vernalis
South Fork Mckenzie St Croix M
illtown
Wh
ite River Centerton Spearman correlation [-]
0 0.25 0.5 0.75 1
Arkansas abov e Pueblo
Arkansas John Martin
Arkansas L as Anima
s
Colorado Ca meo
Colorado Lee's Ferry Colorado Silver Colorado Utah Stateline
Delaware Trenton Green River
Campbells Jackso
n River
Potomac Washington DC San
Joaquin Vernalis
South Fork Mckenzie St Croix M
illtown
Wh
ite River Centerton
Seasonal anomalies water-air temperatrure
GEMS Climatology
Modelling Global Fresh Surface Water Temperature
Conclusions
• Good reproduction of zonal and seasonal temperature variations; over-estimation in tropics; reasonable
reproduction of daily temperatures.
• Large anomalies between surface water and atmospheric temperatures, especially for high latitudes and rivers
traversing multiple climate zones: dedicated water temperature model is a necessity.
