Lectures 3 4 Runoff processes in polar

Lectures 3 & 4 Runoff processes in polar regions s. zhuravlev@spbu. ru 1

The links between energy & water fluxes The energy balance defines: • Snow cold content • The freezing front’s depth in the soil • Melt-freeze processes occurrence • Snowmelt rate The amount of water & the processes of water migration on the watershed Decker et al, 2003

Snowmelt & sloped surface 3

Preferential flow paths 4

Snomelt & unfrozen ground 5

Snomelt & unfrozen ground 6

Snowmelt & frozen ground 7

Snowmelt & sloped surface 8

Hydrologic activities are confined to the active layer Image: Agriculture and Agri-Food Canada

A typical structure of runoff formation

Санкт. Петербургский Университет Groundwater flow Кафедра гидрологии суши

Arctic river hydrographs

River Usa, Bolshezemelskaya Tundra Subarctic nival regime

Санкт. Петербургский Университет Examples – arctic nival regime Кафедра гидрологии суши January February March April May June July August September October December

Санкт. Петербургский Университет Examples – proglacial regime Кафедра гидрологии суши January February March April May June July August September October December

Санкт. Петербургский Университет Examples Кафедра гидрологии суши January February March April May June July August September October December

Санкт. Петербургский Университет Examples Кафедра гидрологии суши

Санкт. Петербургский Университет Examples Кафедра гидрологии суши January February March April May June July August September October December

Санкт. Петербургский Университет Кафедра The hydrological environment гидрологии суши of polar regions (1) The frozen ground often has very low or negligible permeability and therefore acts as an aquiclude. (2) Most hydrologic activities are confined to the active layer, which is the annually frozen and thawed zone overlying the permafrost table. Groundflow is very low (usually less than 10%) (3) Many hydrologic processes become dormant during the long northern winters (4) Permafrost hydrology is allied closely with the hydrology of snow and ice. (5) Energy and water fluxes are strongly linked, especially for snow processes! (6) Runoff regime is characterized by very low (or near-zero) winter flow and high summer floods caused by snowmelting

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