Dr. Sergei Zhuravlev Corelis-2016 St. Petersburg State University

Dr. Sergei Zhuravlev Corelis-2016 St. Petersburg State University 1 1-2. Prel. test. Introduction to hydrometeorology. Water and energy cycles 3-4. Snow & snow processes 5-6. Runoff processes in polar regions. Final test.

Overlook: Current lecture Preliminary quiz (15 min) Hydrological cycle and its components Runoff generation mechanisms Water balance. Variation of water balance components Radiation and heat balance of the polar regions 2

The hydrological cycle 3

The hydrological cycle 4

The hydrological cycle: precipitation: size & types, conditions and mechanisms of generation 5 Conditions: 1 Cooling of the atmosphere 2 Condensation onto nuclei (~0.1-1 µm) 3 Growth of the water/ice droplets Mechanisms: 1 Condensation 2 Collision and coalescence 3 Bergeron process

The hydrological cycle: Cloud condensation nuclei 6

The hydrological cycle: Bergeron process 7

The hydrological cycle: collision and coalescence 8

The hydrological cycle 9

The hydrological cycle: Interception 10 Gross rainfall, R, is the rainfall measured above the vegetative canopy or in the open. Canopy interception loss, Ec, is water that evaporates from the canopy. Throughfall, Rt, is rainfall that reaches the ground surface directly through spaces in the canopy and by dripping from the canopy. Stemflow, Rs, is water that reaches the ground surface by running down trunks and stems. Litter interception loss, El, is water that evaporates from the ground surface (usually Including near-ground plants and leaf litter). Total interception loss, Ei, is the sum of canopy and litter interception losses. Net rainfall, Rn, is the gross rainfall minus the total interception loss. Rn= R – Ei Ei = Ec+ El R = Rt + Rs + Ec Rn = Rt + Rs – El

The hydrological cycle: Interception 11 Interception loss vegetation type density stage of development (LAI) intensity, duration & form of rainfall temperature wind speed air moisture Vegetative Meteorological

The hydrological cycle: Interception loss 12 (Physical hydrology, L. Dingman, 2015)

Basic terms Санкт- Петербургский Университет Кафедра гидрологии суши (WMO Comet program, 2010) 13

Runoff Surface runoff – over the soil surface Runoff - the water or other material that drains freely off the surface of something Subsurface runoff – below the soil surface If you see water moving, it’s runoff River runoff – in the hydrological network [discharge - m3/s] 14

Reasons to study runoff Flood and drought prediction (amnola.com) 2. Water management (D. Spuhler, 2012 ) 3. Civil engineering 15

Terms Watershed - is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point 16

Terms 17 Watershed (used for small-size basins) Catchment Basin (drainage basin)

Terms 18 H mean H low (low flow) H high (floods) 1. F [m2] =B*Hmean 2. Q [m3/s] = F*Vmean В, м

Major Arctic watersheds 19 Runoff volume [ volume per time] Discharge [m3/s] Specific runoff [l/(s*sq.km)]] Runoff per unit area [mm] Runoff coefficient (from 0 to 1)

Water balance equation St. Petersburg State University Chair of hydrology 20

Evapotranspiration 21 Evapotranspiration – the collective tern for all the processes by which water in the liquid or solid phase becomes atmospheric water vapor Evaporation from open water Evaporation from bare soil Transpiration (evaporation from plants) Sublimation (from ice and snow) World average: 60% of the precipitation on the continents is evapotranspirated ET > Runoff in most of the river basins (but not in the polar region) Simple equation for assessment evaporation from water surface

The terrestrial water balance St. Petersburg State University Chair of hydrology (Oki and Kanae, 2006; earlywarn.blogspot.ru) 22

The hydrological cycle: Precipitation – units of measurement and spatial distribution 23 (http://www.climate4you.com) Units-depth of liquid water for a given time period (without specification rain/sleet/snow) Factors: Altitude Latitude Distance from water bodies Aspect

Water balance’s components’ spatial distribution - evapotranspiration (Mu, Q., L. A. Jones, J. S. Kimball, K. C. McDonald and S. W. Running, 2009) 24

Water balance’s components’ spatial distribution - runoff St. Petersburg State University Chair of hydrology (Oki and Kanae, 2006) 25

Runoff distribution St. Petersburg State University Chair of hydrology 26 (riv. Kolyma-Srednekolymsk, year 2014)

Arctic region water balance features St. Petersburg State University Chair of hydrology 27 Small amount of precipitation (av. 450-500 mm, large parties from 200 to 600 mm) Snow – about 70% (October-April), rainfall – about 30% (May-September) Very small ET (av. about 250-300 mm) Large runoff (150-200 mm) because of P - ET Very low flow during the winter Runoff peaks occur in June-July

Energy budget St. Petersburg State University 28

Energy budget St. Petersburg State University 29

Energy budget – incoming solar radiation St. Petersburg State University 30 © Wisconsin State Climatology Office

Annual reflectivity of Earth’s surface St. Petersburg State University 31 © http://www.covis.nwu.edu/

Earth’s surface albedo St. Petersburg State University 32 Briegle et al.1986)

Radiation balance (net radiation) St. Petersburg State University 33 K↓: incoming shortwave radiation ƒK↑: outgoing shortwave radiation K↑= αK↓ L↓: incoming longwave radiation L↓=εsσTs4 L↑: outgoing longwave radiation L ↑ =εoσTo4

Radiation balance (net radiation) St. Petersburg State University 34 H = sensible heat flux: energy used to change temperature of atmosphere LE = latent heat flux: energy used to change state of water G = ground heat flux: energy used to change temperature of subsurface

Radiation balance (net radiation) St. Petersburg State University 35 (Serreze at al. 2006)

Radiation balance (net radiation) St. Petersburg State University 36 (Serreze at al. 2006)

Arctic region energy balance features St. Petersburg State University Chair of hydrology 37 Incoming daily insolation at the top of the atmosphere is from 0 up to 500 W/sq.m Large albedo (up to 0.8) due to snow and ice Annual net flux is positive over Arctic ocean and negative over ground Net flux has large intra-annual variation

Arctic region energy balance features St. Petersburg State University 38 Thank you [email protected]