Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Niño phase at the beginning of the year to a cool La Niña phase by July contributed to many notable events, ranging from record wetness across much of Australia to historically low Eastern Pacific basin and near-record high North Atlantic basin hurricane activity. The remaining five main hurricane basins experienced below- to well-below-normal tropical cyclone activity. The negative phase of the Arctic Oscillation was a major driver of Northern Hemisphere temperature patterns during 2009/10 winter and again in late 2010. It contributed to record snowfall and unusually low temperatures over much of northern Eurasia and parts of the United States, while bringing above-normal temperatures to the high northern latitudes. The February Arctic Oscillation Index value was the most negative since records began in 1950

Lammers, Richard B.

Shiklomanov, Alexander I.

English

UNH Scholars' Repository

University of New HampshireUniversity of New Hampshire Scholars' RepositoryFaculty Publications6-1-2011River Discharge, in Chapter 5, Arctic, State of theClimate in 2010Alexander I. ShiklomanovUniversity of New Hampshire, Durham, alex.shiklomanov@unh.eduRichard B. LammersUniversity of New Hampshire, Durham, richard.lammers@unh.eduFollow this and additional works at: https://scholars.unh.edu/faculty_pubsThis Article is brought to you for free and open access by University of New Hampshire Scholars' Repository. It has been accepted for inclusion inFaculty Publications by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contactnicole.hentz@unh.edu.Recommended CitationShiklomanov A.I. and Lammers R.B. (2011) River Discharge, in Chapter 5, Arctic, State of the Climate in 2010, Bull. Amer. Meteor.Soc., 92 (6), S153-S154.S153STATE OF THE CLIMATE IN 2010 |JUne 2011relatively stable on the North Slope of Alaska (Smith et al. 2010), and there was even a slight decrease (0.1°C–0.3°C) in the Alaskan interior during the last three years. The exception has been at Alaskan coastal sites, which have exhibited continuous warming during the last ten years. The warming trend at the Alaskan coastal sites has been particularly pronounced during the last four to five years (Fig. 5.16a). Data obtained in 2010 in Alaska suggest that the observed warming trend along the coast has begun to propagate south towards the northern foothills of the Brooks Range (approximately 200 km inland), where a noticeable warming in the upper 20 m of permafrost has become evident since 2008 (Fig. 5.16b).A common feature at Alaskan, Canadian, and Russian sites is more significant warming in relatively cold permafrost than in warm permafrost in the same geographical area (Romanovsky et al. 2010b). Permafrost temperature has increased by 1°C to 2°C in northern Russia during the last 30 to 35 years. An especially noticeable temperature increase was observed during the last three years in the Russian Arctic, where the mean annual temperature at 15 m depth increased by > 0.35°C in the Tiksi area and by 0.3°C at 10 m depth in northern European Rus-sia. However, relatively low air temperatures during summer 2009 and the following winter interrupted this warming trend at many locations in the Rus-sian Arctic, especially in the western sector. Data on changes in the active layer thickness (ALT) in the arctic lowlands are less conclusive. In the Alaskan Arctic, ALT experiences a large interannual vari-ability, with no discernible trends; this is likely due to the short length of historical data records and pos-sible surface subsidence upon thawing of the upper, ice-rich permafrost (Streletskiy et al. 2008). At the same time, data from northern Quebec (Smith et al. 2010) and from the Nordic countries (Christiansen et al. 2010) show a distinct increasing trend in ALT during the last two decades.The last 30 years of increasing permafrost tem-peratures have resulted in the thawing of perma-frost in areas of discontinuous permafrost in Russia (Oberman 2008; Romanovsky et al. 2010a). This is evidenced by changes in the depth and number of taliks (a sub-surface layer of year-round unfrozen ground within permafrost), especially in sandy and sandy loam sediments compared to clay. A massive development of new closed taliks in some areas of the continuous permafrost zone, resulting from increased snow cover and warming permafrost, was responsible for the observed northward movement of the boundary between continuous and discontinuous permafrost by several tens of kilometers (Oberman and Shesler 2009; Romanovsky et al. 2010a).3) river discharge—A. I. Shiklomanov and R. B. LammersRiver discharge from Eurasia to the Arctic Ocean during 1936–2009 increased at a mean rate of 2.7 ± 0.5 km3 yr-1. For the six largest Eurasian rivers (Severnaya Dvina, Pechora, Ob, Yenisey, Lena, and Kolyma), the most significant positive trend, 12 km3 yr-1, occurred during the last 23 years (1987–2009; Shiklomanov and Lammers 2009). Data available online from the U.S. Geological Survey (http://waterdata.usgs.gov/ak/nwis) and Environment Canada (http://www.wsc.ec.gc.ca/applications/H2O/index-eng.cfm) for 2009 showed 9% higher discharge Fig. 5.16. Changes in permafrost temperature (a) between 2002 and 2009 at three different depths at the Barrow Permafrost Observatory on the northern-most coast of Alaska, and (b) between 2006 and 2010 at four different depths at the Imnaviat Creek Per-mafrost Observatory near the Toolik Lake research station, Alaska, approximately 200 km south of the Beaufort Sea coast. Note that the coastal permafrost (a) is colder than the inland permafrost (b). The gap in (a) between 15 May 2005 and 23 Sep 2006 is due to a datalogger malfunction.S154 | JUne 2011over the 1969–2008 mean for the four largest North American rivers (Mackenzie, Yukon, Back, and Peel) flowing into the Arctic. Officially-distributed river discharge data are usually processed and published after some delay (Shiklomanov et al. 2006). Through cooperation of the State Hydrological Institute and the Arctic and Antarctic Research Institute (AARI) in St. Petersburg, Russia, river discharge is estimated from the most im-portant Russian monitoring sites in near real-time us-ing provisional stage measurements, air temperature, and river ice data (http://neespi.sr.unh.edu/maps). Due to limited data availability, this technique cannot currently be applied to estimate near real-time river discharge for sites in North America.Using this approach, the total annual discharge from the five largest Eurasian rivers (excluding the Kolyma) flowing into the Arctic Ocean in 2010 was estimated to be 1760 km3, which is slightly higher than the long-term (1936–2009) mean of 1737 km3. In 2010 the Yenisey discharge was 6% higher than the long-term mean and the discharge of both the Lena and Ob basins was close to the mean (Fig. 5.17, inset). During the same period, European Russia rivers (Sev. Dvina and Pechora) had 10% lower flow than the long-term mean. This was expected given the very dry and warm summer in 2010 across European Russia (see Sidebar 7.8). An aggregated hydrograph for the five largest Eurasian rivers, based on provisional discharge esti-mates for 2010, is compared with discharge variability and the long-term mean hydrograph for 1994–2009, when the anthropogenic impact on discharge of these rivers was relatively stable and all variations can be attributed to the climate (Fig. 5.17). Aggregated 2010 Eurasian river discharge to the Arctic Ocean had an earlier spring snowmelt rise leading up to the peak flow and a more rapid recessional limb as the snowmelt pulse declined in the early summer. This is consistent with 2010 snow cover observations (see section 5e4) and expected changes in timing of river discharge due to increased warming in the region (Shiklomanov et al. 2007).4) terrestrial snoW—C. Derksen and R. Brown In 2010, a combination of low winter snow ac-cumulation and above-normal spring temperatures created new record-low spring snow cover duration (SCD) over the Arctic since satellite observations be-gan in 1966. Record persistence of the negative phase of the North Atlantic Oscillation (NAO) during the winter of 2009/10 (Cattiaux et al. 2010) favored cold, dry conditions and below-average snow accumulation over large areas of Eurasia and Alaska (Fig. 5.2b). In the spring, the advection of southerly air masses was responsible for high positive air temperature anomalies over much of Eurasia and the western North American Arctic (Fig. 5.2c), which contributed to early snow melt.Annual SCD anomalies for the 2009/10 snow year (August–July) computed from the NOAA Interactive Multisensor Snow and Ice Mapping System (IMS) 24-km product (Helfrich et al. 2007) show below-average SCD over much of the Arctic land area (Fig. 5.18a). The exception was Scandinavia which, like much of the midlatitude regions, had SCD anomalies that were largely posi-tive. The difference in the sign of the SCD anomalies for the Arctic (posi-tive) versus the midlatitudes (negative) reflects the Warm Arctic-Cold Contin-ent atmospheric circulation pattern described in section 5b. Snow cover duration was computed separately for the first (August–January) and second (February–July) halves of the 2009/10 snow year using the weekly NOAA Climate Data Record (CDR; maintained at Rutgers University) to provide information on changes in the start and end dates of snow cover. While the timing of the onset of snow Fig. 5.17. Aggregate daily discharge hydrograph of the five largest rivers in the Eurasian Arctic in 2010 (solid black line) and long-term mean hydrograph (dashed black line) with discharge variation (gray area) during 1994–2009. Inset shows 2010 (black bars) and 1994–2009 (gray bars) anomalies relative to the long-term mean during 1936–2009 for these five rivers. Provisional estimates of annual discharge in 2010 for the five major Eurasian Arctic rivers are based on near real time data.

River Discharge, in Chapter 5, Arctic, State of the Climate in 2010

University of New Hampshire

University of New Hampshire
University of New Hampshire Scholars' Repository
Faculty Publications
6-1-2011
River Discharge, in Chapter 5, Arctic, State of the
Climate in 2010
Alexander I. Shiklomanov
University of New Hampshire, Durham, alex.shiklomanov@unh.edu
Richard B. Lammers
University of New Hampshire, Durham, richard.lammers@unh.edu
Follow this and additional works at: https://scholars.unh.edu/faculty_pubs
This Article is brought to you for free and open access by University of New Hampshire Scholars' Repository. It has been accepted for inclusion in
Faculty Publications by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact
nicole.hentz@unh.edu.
Recommended Citation
Shiklomanov A.I. and Lammers R.B. (2011) River Discharge, in Chapter 5, Arctic, State of the Climate in 2010, Bull. Amer. Meteor.
Soc., 92 (6), S153-S154.
S153STATE OF THE CLIMATE IN 2010 |JUne 2011
relatively stable on the North Slope of Alaska (Smith et 
al. 2010), and there was even a slight decrease (0.1°C–
0.3°C) in the Alaskan interior during the last three 
years. The exception has been at Alaskan coastal sites, 
which have exhibited continuous warming during 
the last ten years. The warming trend at the Alaskan 
coastal sites has been particularly pronounced during 
the last four to five years (Fig. 5.16a). Data obtained 
in 2010 in Alaska suggest that the observed warming 
trend along the coast has begun to propagate south 
towards the northern foothills of the Brooks Range 
(approximately 200 km inland), where a noticeable 
warming in the upper 20 m of permafrost has become 
evident since 2008 (Fig. 5.16b).
A common feature at Alaskan, Canadian, and 
Russian sites is more significant warming in relatively 
cold permafrost than in warm permafrost in the 
same geographical area (Romanovsky et al. 2010b). 
Permafrost temperature has increased by 1°C to 2°C 
in northern Russia during the last 30 to 35 years. 
An especially noticeable temperature increase was 
observed during the last three years in the Russian 
Arctic, where the mean annual temperature at 15 m 
depth increased by > 0.35°C in the Tiksi area and 
by 0.3°C at 10 m depth in northern European Rus-
sia. However, relatively low air temperatures during 
summer 2009 and the following winter interrupted 
this warming trend at many locations in the Rus-
sian Arctic, especially in the western sector. Data on 
changes in the active layer thickness (ALT) in the 
arctic lowlands are less conclusive. In the Alaskan 
Arctic, ALT experiences a large interannual vari-
ability, with no discernible trends; this is likely due 
to the short length of historical data records and pos-
sible surface subsidence upon thawing of the upper, 
ice-rich permafrost (Streletskiy et al. 2008). At the 
same time, data from northern Quebec (Smith et al. 
2010) and from the Nordic countries (Christiansen 
et al. 2010) show a distinct increasing trend in ALT 
during the last two decades.
The last 30 years of increasing permafrost tem-
peratures have resulted in the thawing of perma-
frost in areas of discontinuous permafrost in Russia 
(Oberman 2008; Romanovsky et al. 2010a). This is 
evidenced by changes in the depth and number of 
taliks (a sub-surface layer of year-round unfrozen 
ground within permafrost), especially in sandy and 
sandy loam sediments compared to clay. A massive 
development of new closed taliks in some areas of 
the continuous permafrost zone, resulting from 
increased snow cover and warming permafrost, was 
responsible for the observed northward movement of 
the boundary between continuous and discontinuous 
permafrost by several tens of kilometers (Oberman 
and Shesler 2009; Romanovsky et al. 2010a).
3) river discharge—A. I. Shiklomanov and R. B. Lammers
River discharge from Eurasia to the Arctic Ocean 
during 1936–2009 increased at a mean rate of 2.7 
± 0.5 km3 yr-1. For the six largest Eurasian rivers 
(Severnaya Dvina, Pechora, Ob, Yenisey, Lena, 
and Kolyma), the most significant positive trend, 
12 km3 yr-1, occurred during the last 23 years 
(1987–2009; Shiklomanov and Lammers 2009). Data 
available online from the U.S. Geological Survey 
(http://waterdata.usgs.gov/ak/nwis) and Environment 
Canada (http://www.wsc.ec.gc.ca/applications/H2O/
index-eng.cfm) for 2009 showed 9% higher discharge 
Fig. 5.16. Changes in permafrost temperature (a) 
between 2002 and 2009 at three different depths at 
the Barrow Permafrost Observatory on the northern-
most coast of Alaska, and (b) between 2006 and 2010 
at four different depths at the Imnaviat Creek Per-
mafrost Observatory near the Toolik Lake research 
station, Alaska, approximately 200 km south of the 
Beaufort Sea coast. Note that the coastal permafrost 
(a) is colder than the inland permafrost (b). The gap 
in (a) between 15 May 2005 and 23 Sep 2006 is due to 
a datalogger malfunction.
S154 | JUne 2011
over the 1969–2008 mean for the four largest North 
American rivers (Mackenzie, Yukon, Back, and Peel) 
flowing into the Arctic. 
Officially-distributed river discharge data are 
usually processed and published after some delay 
(Shiklomanov et al. 2006). Through cooperation of 
the State Hydrological Institute and the Arctic and 
Antarctic Research Institute (AARI) in St. Petersburg, 
Russia, river discharge is estimated from the most im-
portant Russian monitoring sites in near real-time us-
ing provisional stage measurements, air temperature, 
and river ice data (http://neespi.sr.unh.edu/maps). 
Due to limited data availability, this technique cannot 
currently be applied to estimate near real-time river 
discharge for sites in North America.
Using this approach, the total annual discharge 
from the five largest Eurasian rivers (excluding the 
Kolyma) flowing into the Arctic Ocean in 2010 was 
estimated to be 1760 km3, which is slightly higher 
than the long-term (1936–2009) mean of 1737 km3. 
In 2010 the Yenisey discharge was 6% higher than 
the long-term mean and the discharge of both the 
Lena and Ob basins was close to the mean (Fig. 5.17, 
inset). During the same period, European Russia 
rivers (Sev. Dvina and Pechora) had 10% lower flow 
than the long-term mean. This was expected given the 
very dry and warm summer in 2010 across European 
Russia (see Sidebar 7.8). 
An aggregated hydrograph for the five largest 
Eurasian rivers, based on provisional discharge esti-
mates for 2010, is compared with discharge variability 
and the long-term mean hydrograph for 1994–2009, 
when the anthropogenic impact on discharge of these 
rivers was relatively stable and all variations can be 
attributed to the climate (Fig. 5.17). Aggregated 2010 
Eurasian river discharge to the Arctic Ocean had 
an earlier spring snowmelt rise leading up to the 
peak flow and a more rapid recessional limb as the 
snowmelt pulse declined in the early summer. This 
is consistent with 2010 snow cover observations (see 
section 5e4) and expected changes in timing of river 
discharge due to increased warming in the region 
(Shiklomanov et al. 2007).
4) terrestrial snoW—C. Derksen and R. Brown 
In 2010, a combination of low winter snow ac-
cumulation and above-normal spring temperatures 
created new record-low spring snow cover duration 
(SCD) over the Arctic since satellite observations be-
gan in 1966. Record persistence of the negative phase 
of the North Atlantic Oscillation (NAO) during the 
winter of 2009/10 (Cattiaux et al. 2010) favored cold, 
dry conditions and below-average snow accumulation 
over large areas of Eurasia and Alaska (Fig. 5.2b). 
In the spring, the advection of southerly air masses 
was responsible for high positive air temperature 
anomalies over much of Eurasia and the western 
North American Arctic (Fig. 5.2c), which contributed 
to early snow melt.
Annual SCD anomalies for the 2009/10 snow year 
(August–July) computed from the NOAA Interactive 
Multisensor Snow and Ice Mapping System (IMS) 
24-km product (Helfrich et al. 2007) 
show below-average SCD over much 
of the Arctic land area (Fig. 5.18a). The 
exception was Scandinavia which, like 
much of the midlatitude regions, had 
SCD anomalies that were largely posi-
tive. The difference in the sign of the 
SCD anomalies for the Arctic (posi-
tive) versus the midlatitudes (negative) 
reflects the Warm Arctic-Cold Contin-
ent atmospheric circulation pattern 
described in section 5b. Snow cover 
duration was computed separately 
for the first (August–January) and 
second (February–July) halves of the 
2009/10 snow year using the weekly 
NOAA Climate Data Record (CDR; 
maintained at Rutgers University) to 
provide information on changes in 
the start and end dates of snow cover. 
While the timing of the onset of snow 
Fig. 5.17. Aggregate daily discharge hydrograph of the five largest 
rivers in the Eurasian Arctic in 2010 (solid black line) and long-term 
mean hydrograph (dashed black line) with discharge variation (gray 
area) during 1994–2009. Inset shows 2010 (black bars) and 1994–2009 
(gray bars) anomalies relative to the long-term mean during 1936–
2009 for these five rivers. Provisional estimates of annual discharge 
in 2010 for the five major Eurasian Arctic rivers are based on near 
real time data.


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