St. Petersburg State University Dr. Sergei Zhuravlev Corelis-2016 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. 1
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 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 5
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 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 10
The hydrological cycle: Interception loss Vegetative vegetation type density stage of development (LAI) Meteorological intensity, duration & form of rainfall temperature wind speed air moisture 11
The hydrological cycle: Interception loss Point of meas. Community Ec/R Hampshire, UK Norway spruce 0. 48 NE Scotland, UK Scots pine 0. 42 Castricum, Holland Oak forest 0. 22 Manaus, Brazil Amazonian rain forest 0. 09 Nigeria Forest-savannah boundary 0. 05 (Physical hydrology, L. Dingman, 2015) 12
Санкт. Петербургский Университет Basic terms Кафедра гидрологии суши (WMO Comet program, 2010) 13
Runoff - the water or other material that drains freely off the surface of something Surface runoff – over the soil surface Subsurface runoff – below the soil surface River runoff – in the hydrological network [discharge - m 3/s] If you see water moving, it’s runoff 14
Reasons to study runoff 1. Flood and drought prediction (amnola. com) 2. Water management 3. Civil engineering 15 (D. Spuhler, 2012 )
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 Watershed (used for small-size basins) Catchment Basin (drainage basin) 17
Terms H high (floods) H mean H low (low flow) В, м 1. F [m 2] =B*Hmean 2. Q [m 3/s] = F*Vmean 18
Major Arctic watersheds River F, mln sq. km Length, km Runoff volume, km 3/y P, mm Yenisey 2. 6 3500 603 430 Lena 2. 5 4400 525 390 Ob 3. 0 3650 404 450 Mackenzie 1. 8 1750 333 360 Runoff volume [ volume per time] Discharge [m 3/s] Specific runoff [l/(s*sq. km)]] Runoff per unit area [mm] 19 Runoff coefficient (from 0 to 1)
St. Petersburg State University Water balance equation Chair of hydrology 20
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 Sublimation (from ice and snow) Transpiration (evaporation from plants) 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 21
St. Petersburg State University The terrestrial water balance Chair of hydrology 22 (Oki and Kanae, 2006; earlywarn. blogspot. ru)
The hydrological cycle: Precipitation – units of measurement and spatial distribution Units-depth of liquid water for a given time period (without specification rain/sleet/snow) Factors: Altitude Latitude Distance from water bodies Aspect (http: //www. climate 4 you. com) 23
Water balance’s components’ spatial distribution - evapotranspiration (Mu, Q. , L. A. Jones, J. S. Kimball, K. C. Mc. Donald and S. W. Running, 2009) 24
St. Petersburg State University Water balance’s components’ spatial distribution - runoff (Oki and Kanae, 2006) Chair of hydrology 25
St. Petersburg State University Runoff distribution Chair of hydrology (riv. Kolyma-Srednekolymsk, year 2014) 26
St. Petersburg State University Arctic region water balance features Chair of hydrology • 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 27
St. Petersburg State University Energy budget 28
St. Petersburg State University Energy budget 29
St. Petersburg State University Energy budget – incoming solar radiation © Wisconsin State Climatology Office 30
St. Petersburg State University Annual reflectivity of Earth’s surface © http: //www. covis. nwu. edu/ 31
St. Petersburg State University Earth’s surface albedo Briegle et al. 1986) 32
St. Petersburg State University Radiation balance (net radiation) K↓: incoming shortwave radiation K↑: outgoing shortwave radiation K↑= αK↓ L↓: incoming longwave radiation L↓=εsσTs 4 L↑: outgoing longwave radiation L ↑ =εoσTo 4 33
St. Petersburg State University Radiation balance (net radiation) 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 34
St. Petersburg State University Radiation balance (net radiation) (Serreze at al. 2006) 35
St. Petersburg State University Radiation balance (net radiation) (Serreze at al. 2006) 36
St. Petersburg State University Arctic region energy balance features Chair of hydrology • 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 37
St. Petersburg State University Arctic region energy balance features Thank you s. zhuravlev@spbu. ru 38
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Lecture 1-2 Introduction. Water & energy cycle.ppt