Zooming out:

Sina Muster, Julia Boike, Moritz Langer, Annett Bartsch, Anne Morgenstern, Guido Grosse, Kurt Roth

Zooming out:

From local snapshots to a pan-arctic

inventory of Arctic ponds and lakes

Water bodies in the Arctic are ubiquitious.

Bathurst Island, Canadian High Arctic

Thermal contraction crack polygons

Mackenzie Delta, Canada

Mackenzie Delta, Canada

Baffin Island, Canadian High Arctic

Permafrost, Julia Boike, 2010

Examples: Thermokarst

Coastal lowlands, Laptev Sea, Siberia

Ponds emit 40% of landscape–scale CO₂ emissions in Siberian polygonal tundra in the Lena Delta.

(Abnizova et al., GBC 2012)

During freezing ponds

produce as much CH₄ per square meter as the

average tundra landscape during summer

(Langer et al., RSE, 2014)

Ponds as biogeochemical hotspots

Ponds = water bodies with surface area smaller than 100x100 m

Limits of Global Inventories

• Ponds and small lakes are not mapped on the pan-arctic

scale

• Global lakes and wetland

database (GLWD) maps lakes larger 0.1 km² (100*1000 m)

• MODIS water mask has a resolution of 250 m -> yields confident lake areas larger 0.25 km² (500 x 500 m)

8

Source: Lehner & Döll, 2004

Scientific questions

1. How many ponds and small lakes are there?

2. How can we scale high-resolution but

local water body maps to the global

scale?

Sites

Lena Delta Yukon Delta

Kolyma Lowlands

Yamal Peninsula Polar Bear Pass

Mackenzie Delta

Seward Peninsula Barrow Peninsula

Baku Seoul

Minsk

Tehran Moscow

T'Bilisi Stockholm

P'yongyang

Copenhagen RigaRiga OsloOslo

Astana Astana

Vilnius Vilnius Helsinki Helsinki

Ulaanbaatar Ulaanbaatar

040W

140W

60W

20W 80W

160W

120W

180W

100W

60E

40E 80E

120E 140E

20E

100E 160E

180E

60N

80N

40N 40N

Permafrost

continuous (90-100%) discontinuous (50-90%) isolated patches 0-10%) sporadic (10-50%)

(after Brown et al. 1997)

0 2.5 5 10km

High-resolution mapping

• Kompsat-2, TerraSAR-X, Geoeye, aerial photos

• 0.3 m to 4 m resolution

• 2 km² to 500 km² coverage

5 km

regional

size distributions

Upscaling scheme

12

regional fraction of water surface

unmixing low-resolution

satellite data

representative water body count

High-resolution maps

Representative water body count

13 13

Arga Complex

First Terrace Ice

Complex

(1) Minimum sampling area

(2) Variability within the region

Lena Delta, Siberia

Similar

conditions for lake ice

formation and growth?

Regional probability density functions

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Lena Delta Barrow Peninsula

Polar Bear Pass Mackenzie Delta

Δp=0.15

Δp=0.02 Δp=0.02

mapped not mapped

Barrow Lena Delta

Inter-regional variability: number and area

15

80 to 99% of the water body number are not mapped

mapped not mapped

5 to 50 % of the

water body area are not mapped

16 16

Upscaling to Pan-Arctic Lake Distribution

error N = xA^y

Lena Delta, Siberia

Muster et al., RS, 2013

Conclusions

 We need to zoom in before we can zoom out.

• Ensure that probability density functions are representative

• quantify regional variability to give a measure of uncertainty

 Representative regional probability density functions can then be used to implement subgrid-scale

information in coarse-scale grids.

Photos courtesy of:

Julia Boike | Konstanze Piel | J.A. Kraulis/Corbis

Thank you!