Supplement of Biogeosciences, 12, 5811–5829, 2015
http://www.biogeosciences.net/12/5811/2015/
doi:10.5194/bg-12-5811-2015-supplement
© Author(s) 2015. CC Attribution 3.0 License.
Supplement of
The role of snow cover affecting boreal-arctic soil freeze–thaw and carbon
dynamics
Y. Yi et al.
Correspondence to: Y. Yi ([email protected])
The copyright of individual parts of the supplement might differ from the CC-BY 3.0 licence.
1 Table S1 The 20 FLUXNET eddy-covariance (EC) tower sites within the pan-Arctic basin and
2 Alaska domain used for model validation.
1
Site
US-Bn1
CA-NS1
CA-NS2
CA-NS3
CA-NS5
CA-Ojp
CA-SF1
CA-SF2
CA-Man
CA-Obs
CA-Qfo
RU-Zot
US-Bn2
CA-Oas
CA-WP1
CA-Gro
RU-Che
CA-Let
FI-Kaa
US-Ivo
Lat, Lon
63.92°N, 145.38°W
55.88°N, 98.48°W
55.91°N, 98.52°W
55.91°N, 98.38°W
55.86°N, 98.48°W
53.92°N, 104.69°W
54.49°N, 105.82°W
54.25°N, 105.88°W
55.88°N, 98.48°W
53.99°N, 105.12°W
49.69°N, 74.34°W
60.80°N, 89.35°W
63.92°N, 145.38°W
53.63°N, 106.20°W
54.95°N, 112.47°W
48.22°N, 82.15°W
68.61°N, 161.34°W
49.71°N, 112.94°W
69.14°N, 27.30°W
68.49°N, 155.75°W
2
Biome type
ENF
ENF
ENF
ENF
ENF
ENF
ENF
ENF
ENF
ENF
ENF
ENF
DBF
DBF
MXF
MXF
MXF
GRS
WET
Tundra
Observation period
2003-2003
2003-2004
2002-2004
2002-2004
2002-2004
2000-2005
2004-2005
2003-2004
2000-2003
2000-2005
2004-2006
2002-2003
2003-2003
2000-2005
2004-2005
2004-2005
2003-2003
2003-2005
2000-2006
2004-2006
3 1
FLUXNET Site Identifier;
4 2
Dominant biome type within the tower footprint: ENF: evergreen needle-leaf forest; DBF:
5 deciduous broadleaf forest; MXF: mixed forest; GRS: grassland; WET: wetland.
1 Table S2 The model prescribed fraction (percentage) of leaf, fine root and woody components of
2 litterfall for each model biome type based on White et al. (2000).
3 Biome type
Leaf (%)
Tundra
Forest-tundra
Taiga-boreal
Grasslands/steppe/Shrubland
Wetland
Deciduous/mixed forest
32
28
24
28
36
24
Fine roots
(%)
48
42
36
42
54
36
Wood (%)
20
30
40
30
10
40
1 Table S3 Prescribed labile, cellulose and lignin fractions (percentage) of leaf, fine root and
2 woody litterfall (White et al. 2000), used to partition model litterfall and relative
3 decomposability in the soil decomposition model.
Leaf
Fine roots
Wood
4 Labile (%)
Cellulose (%)
Lignin (%)
55
34
0
31
44
71
14
22
29
1 2 3 0.39 5 6 7 8 0.29 0.55
CO2 4 Litter3 Ƭ=0.19
Littter2 Ƭ=0.038
Littter1 Ƭ=0
0.0023 CO
O2 CO 2
SO
OC1 Ƭ=0
0.038 SOC3 Ƭ=2.0
SO
OC2 Ƭ=
=0.19
0.28
8 CO2
0.46
0.55 CO2
C
CO2 SOC4 Ƭ=27
9 1.0 10 CO2 11 S The poo
ol structure, transitions, respired ffractions (nuumbers on the arrows)) and
Figure S1.
12 turnover rates for thee soil organiic carbon (S
SOC) decom
mposition moodel (numberrs in the elliipses,
13 yr-1). Thee SOC pools include 3 litterfall pools, 3 SOC pools with relatively faast turnover rates
14 (SOC1-3) and a deep
p SOC pool (SOC4)
(
with
h relatively sslow turnoveer.
1 2 3 Figure S2
2. The merg
ged land cov
ver map baseed on the MO
ODIS Collection 5 IGB
BP land coveer and
4 CAVM classification
c
ns. Tundra, forest-tundra
f
a and taiga/bboreal biomees account ffor 18.1%, 31.4%
5 and 20.0%
% of the pan
n-Arctic basiin and Alask
ka study areaa, respectively.
1 2 3 Figure S3
3. Comparisons of simullated NEE flluxes using ddynamical liitterfall alloccation and evvenly
4 distributeed litterfall schemes at a deciduou
us broadleaff forest (DB
BF) tower siite. The dynnamic
5 litterfall allocation
a
sccheme was based
b
on sateellite NDVI time series ((Appendix A
A2), and the daily
6 proportio
on of annual total litterfaall is shown as Litterfalll_ratio. NEE
E_obs indicaates the toweer EC
7 observed
d NEE flux
xes, NEE_dynamic_littterfall and NEE_evenn_litterfall rrepresent m
model
8 simulated
d NEE flux
xes using th
he dynamic litterfall all ocation andd evenly disstributed littterfall
9 schemes,, respectively
y.
1 2 3 Figure S4. Comparissons of mod
del simulateed surface sooil moisturee (~ 5 cm ddepth) and inn situ
4 measurem
ments at the Imnavait Crreek, AK tun
ndra tower vvalidation sitte. Only the measuremennts at
5 the dry heath
h
tundraa site were included
i
du
ue to paucityy of soil mooisture data at the otherr two
6 tundra sittes. The yeaar 2008 was not
n included
d due to relat
atively few m
measurementts available aat the
7 dry heath
h tundra sitee. Generally, different so
oil moisture datasets aree not directlyy comparable due
8 to differeent statisticaal moments and system
matic bias. T
Therefore, thhe modeledd and in situu soil
9 moisture records weere scaled to
o a consisten
nt mean andd standard ddeviation beffore comparrisons
10 following
g Koster et al.
a (2009). Note
N that the simulated s oil moisturee during the winter was m
much
11 lower thaan the tower measuremen
nts prior to the
t scaling.
1 2 3 Figure S5. Comparissons of mod
del simulated
d soil moistuure at differeent depths (18, 41cm) aand in
4 situ meaasurements at
a a mature boreal foresst site in M
Manitoba, CA
AN. The year 2002 waas not
5 included due to relaatively few measuremen
nts availablee for that yyear. Similarr as Fig. S44, the
6 simulated
d soil moistu
ure was resccaled to matcch the mean and standarrd deviation of the in situu soil
7 moisture data prior to
o the comparrison.
1 2 3 Figure S6
6. (a) Distrib
bution of 53 Circumpolaar Active Laayer Monitorring (CALM
M) tundra sitees (as
4 indicated
d by black dots)
d
used fo
or model AL
LD validatioon; (b) Com
mparisons of model simuulated
5 ALD verrsus the CAL
LM observattions. The diistribution off CALM sitees was show
wn over the m
model
6 simulated
d mean (198
82-2010) AL
LD map. Th
he comparisoons were maade at differrent periods from
7 1982 to 2010
2
since CALM
C
obserrvations span
n different peeriods.
1 2 3 S Correlatiions betweeen cold-seasson (from N
November tto April) caarbon fluxess and
Figure S7.
4 climate variables
v
(in
ncluding cold
d-season air temperaturee Tair, SWE
E and SCE). The correlaations
5 were bin
nned into 2.5
5 °C intervaals of annuall mean Tairr. The standdard deviatioon of correlaations
6 across eaach climate zone
z
is show
wn through th
he error barss.
1 2 3 Figure S8. (a) Simullated temporral trends (u
unit: yr-1) in the ratio of the warm-season (MJJA
ASO)
4 m the upper soil
s (≤0.5m) organic carbbon (SOC) ppool to total Rh for the m
model
Rh contriibution from
5 sensitivitty analysis runs from 1982
1
to 201
10. The zonnal-averagess of Rh ratiio trends foor the
6 sensitivitty analysis are
a shown in
n (b). For th
he sensitivitty analysis, the model w
was driven uusing
7 different surface meeteorology datasets.
d
Run
n1 indicates model simuulations bassed on varyiing T
8 and P in
nputs; Run2 indicates model
m
simulaations basedd on varyingg T inputs alone; and Run3
9 indicates the model simulations
s
based
b
on varrying P inputts alone.
1 References
2 Koster, R. D., Guo, Z. C., Yang, R. Q., Dirmeyer, P. A., Mitchell, K., and Puma, M. J.: On the
3 Nature of Soil Moisture in Land Surface Models, J Climate, 22, 4322-4335, 2009.