I HM Flashcards

Question

Implications Hydrological Cycle (Read)

Answer 1

* Provides continuous supply of fresh water * More than half of the rainfall over land lost as evaporation * Runoff: Diverted for human uses; lost to the oceans * "Climate conditioning system"

Answer 2

Latent heat Sunlight evaporates water from ocean/other surfaces --\> energy is stored in form of latent hear in water vapor --\> energy loss by condensation

Answer 3

in W/m² Incoming solar radiation: 340 Outgoing Longwave Radiation: 235

Answer 4

Important Parameter T_o (surface temperature) Unit: Daily radiation: (kW/m² day) Mean annual global radiation (W/m²) (Watt)

Answer 5

- P over oceans is 3.5 x greater than on land - E over oceans is 6 x greater than on land - Annual renewed fresh water volume amounts only ~ 40 000 km - On average 64 % of P on land is lost by E

Answer 6

Globe total: **_NH %_** P = 100 E = 90 R =10 **_SH %_** ``` P = 100 E = 110 R = -10 ``` Bei _nur Land Area Betrachung_ ungefähr beide bei zwei Drittel zu ein Drittel E/R Bei _nur Ocean Area Betrachtung_ beide ungefähr so wie SH oben, SH etwas ausgeprägter in 10³ km³

Answer 7

* Almost no differences in precipitation * NH provides 46.1 %, SH 53.9 % of E * SH has surplus of E which is transported as water vapor to the NH * NH gains water which is transported by ocean currents to the SH

Answer 8

850 mm Precipitation 500 mm ET Rest 50/50 Run-off / GW

Answer 9

Not stressed: \> 1700 m³ / person-y Stressed: \< 500 m³ / person-y

Answer 10

* E is partly absorbed by atmosphere (absorption bands of greenhouse gases) * reemitted to all directions * downward part E_a

Answer 11

* difference between terrestrial E and back radiation E_a * E_eff = E - E_a * under clear sky E_a ~ 75% of E

Answer 12

Surface water balance: P = (ET) + R

Answer 13

Most positive: Equator Most negative: The two pols

Answer 14

Ferrel cell (between 30 -60 between the two co-rotating Hadley and Polar Cells Anti-Clockwise (NH) Die instabile Ferrel-Zelle – Westwinddrift Zwischen den beiden gleichläufigen Systemen Hadley- und Polarzelle jeder Halbkugel passt je ein drittes gegenläufiges, nicht unähnlich dem Ineinandergreifen von Zahnrädern. Dort wird in Bodennähe Luft polwärts verlagert, woraus unter Einwirkung der Jetstreams westliche Winde entstehen. Die Zone heißt daher auch Westwindzone oder Westwinddrift der gemäßigten Breiten. Sie ist die instabilste, weil auf rund 60° bis 70° geographischer Breite die feuchtwarmen Westwinde auf kalte polare Ostwinde treffen: die Polarfront bildet sich. Die Ferrel-Zelle (nach William Ferrel) ist die Zelle größter (Sonnen-)Energieunterschiede (und damit verbunden auch Temperaturunterschiede). In ihr befinden sich ca. 38 % des gesamten Energieunterschieds zwischen Innerentropen und den Polen. Die äquatorseitige Grenze liegt bei rund 35° Breite. Part of the air rising at 60° latitude diverges at high altitude toward the poles and creates the polar cell. The rest moves toward the equator where it collides at 30° latitude with the high-level air of the Hadley cell. There it subsides and strengthens the high pressure ridges beneath. A large part of the energy that drives the Ferrel cell is provided by the polar and Hadley cells circulating on either side and that drag the Ferrel cell with it.[5] The Ferrel cell, theorized by William Ferrel (1817–1891), is therefore a secondary circulation feature, whose existence depends upon the Hadley and polar cells on either side of it. It might be thought of as an eddy created by the Hadley and polar cells. The Ferrel cell is weak, and the air flow and temperatures within it are variable. For this reason, the mid-latitudes are sometimes known as the "zone of mixing." At high altitudes, the Ferrel cell overrides the Hadley and Polar cells. The air of the Ferrel cell that descends at 30° latitude returns poleward at the ground level, and as it does so it deviates toward the east. In the upper atmosphere of the Ferrel cell, the air moving toward the equator deviates toward the west. Both of those deviations, as in the case of the Hadley and polar cells, are driven by conservation of angular momentum. As a result, just as the easterly Trade Winds are found below the Hadley cell, the Westerlies are found beneath the Ferrel cell. The forces driving the flow in the Ferrel cell are weak, and so the weather in that zone is variable. Thus, strong high-pressure areas which divert the prevailing westerlies, such as a Siberian high, can override the Ferrel cell, making it discontinuous. While the Hadley and polar cells are truly closed loops, the Ferrel cell is not, and the telling point is in the Westerlies, which are more formally known as "the Prevailing Westerlies." The easterly Trade Winds and the polar easterlies have nothing over which to prevail, as their parent circulation cells are strong enough and face few obstacles either in the form of massive terrain features or high pressure zones. The weaker Westerlies of the Ferrel cell, however, can be disrupted. The local passage of a cold front may change that in a matter of minutes, and frequently does. As a result, at the surface, winds can vary abruptly in direction. But the winds above the surface, where they are less disrupted by terrain, are essentially westerly. A low pressure zone at 60° latitude that moves toward the equator, or a high pressure zone at 30° latitude that moves poleward, will accelerate the Westerlies of the Ferrel cell. A strong high, moving polewards may bring westerly winds for days. The Ferrel cell is driven by the Hadley and Polar cells. It has neither a strong source of heat nor a strong sink to drive convection. As a result, the weather within the Ferrel cell is highly variable and is influenced by changes to the Hadley and Polar cells. The base of the Ferrel cell is characterized by the movement of air masses, and the location of those air masses is influenced in part by the location of the jet stream, even though it flows near the tropopause. Overall, the movement of surface air is from the 30th latitude to the 60th. However, the upper flow of the Ferrel cell is weak and not well defined. In contrast to the Hadley and Polar systems, the Ferrel system provides an example of a thermally indirect circulation. The Ferrel system acts as a heat pump with a coefficient of performance of 12.1, consuming kinetic energy at an approximate rate of 275 terawatts

Answer 15

1. Thermal pressure systems (Ferrel) 2. Dynamic pressure systems

Answer 16

- seasonal change - summer: air over continents more heated than over oceans - drop of pressure from ocean to land - near-surface thermal low over continents - winter: stong cooling of continents (negative radiation balance) - near-surface cold continental high - large land-sea-breeze-system --\> thermally caused (e.g. monsoon)

Answer 17

* driver: differences in the energy balance --\> energy surplus in the tropics, energy deficit at higher latitudes * Coriolis effect / force * no direct meridional compensating flow possible * deflection by Coriolis: NH to right, SH to left --\> formation of permanent H and L

Answer 18

**_low:_** rising air masses, condensation, formation of clouds. precipitation, cyclonic rotation, air masses "sucked in" **_high:_** sinking air masses, droplets evaporate, no clouds, no precipitation, anti-cyclonic rotation, air masses "flow out" **_Coriolis "force":_** deflects air masses to the right (N) or left (S-Hemisohere)

Answer 19

max. evaporation possible

Answer 20

Real evaporation ## Footnote (over a free water surface actual can equal potential evaporation)

Answer 21

Evaporation of water from stomata openings in leaves of plants

Answer 22

Evapotranspiration = Evaporation + Interception + Transpiration Forest: 10E, 30I, 60T Grassland: 25E, 25I, 50T Farmland: 45 E, 15I, 40T Soil: 100E

Answer 23

P \> E P \< E

Answer 24

Evapotranspiration [mm] decreases with height - Isolines of evapotranspiration

Answer 25

Yes, but: sometimes there are quality issues: --\> chemicals, pathogens sometimes there are spacial distribution issues: freshwater resources in Norway per person versus freshwater resources in Saudi Arabia per person

Answer 26

_Findings from the table:_ - Industrial countries consume more meat than vegetables (total in l/d: IC: 3600, DC: 2050) - Meat diet is more water intensive than vegetable diet (difference in l/d: IC: 1300, DC: 300) -

Answer 27

* Especially in Asia, Central-West Africa, East Coast of S.Am., Europe neglectable

Answer 28

Whole subsaharan africa a problem.. Even Congo.. Same same for subsaharan africa. In addition, India, South-East Asia

Answer 29

Inflitration, run off

Answer 30

Climatic aspects, evapotrans.

Answer 31

Evapotranspiration

Answer 32

NH! Equator!

Answer 33

* measure for reflectance or optical brightness of a surface * scale from zero (corresponding to a black body that absorbs all incident radiation) to one (corresponding to a white body that reflects all incident radiation) snow: up to 0.8-0.9 clouds: 0.6-0.9 desert: 0.3 forest: 0.05

Answer 34

* (ITCZ) * a region of equatorial lows * area encircling Earth near the Equator, where the northeast and southeast trade winds converge

Answer 35

**_E / P as indicator:_** Between Australia: 0.94 and Antarctica: 0.17 (Africa 0.84) --\> **_R / P_**: Australia: 0.06 usw. More rain in Africa, more evaporation. * Volumes are highest in Asia * Africa characterized by high E and relative low R * Africa, Europe, Australia: --\> Runoff around 30% * Europe, Americas: --\> Runoff around 50% * Highest precipitation in S-America (tropical forests, Andes)

Answer 36

Property of water: Molecues tend to stick to one another Water is attracted to other water Surface tension = cohesion forces

Answer 37

Rws = (W - S) / Q W: annual withdrawal by all sectors S: water use from desalinated water Q: annual RFWR --\> High water stress: Rws \> 0.4

Answer 38

Property of water: Molecules tend to stick to objects Water is attracted to other materials Capillary action = adhesion forces

Answer 39

in its solid phase it is less dense than in its liquid phase

Answer 40

Highest at 4 degrees

Answer 41

is a pore, found in the epidermis of leaves

Answer 42

amount of energy required to change the temperature of a substance (by 1 °C) Water has high specific heat --\> can absorb large amounts of heat energy before it gets hot --\> releases heat energy slowly

Answer 43

Water good with heat conduction --\> Water is perfect for heating due to its high specific heat and capability of conduction

Answer 44

when ice, water and vapor can coexxist (around 0 degrees)

Answer 45

q [g / kg] atio of the mass of water vapor (in a sample of moist air) to the total mass of the sample

Answer 46

V_d _{[g / m³]} vapor densitiy mass of water vapor per unit volume of air

Answer 47

RH [%] = ( e / E) \* 100 ratio between actual (e) and saturation (e_s, e_sat, E) vapor pressure at a given temperature

Answer 48

- E is the maximum of vapor in the atmosphere without condensation - E depends on the temperature, not air pressure - Eabove water is higher than above ice

Answer 49

Preconditions: - water vapor saturated air (moist air must be cooled to its dew point = Kondensationspunkt) - phase transition (--\> presence of condensation nuclei) - growth of water droplets

Answer 50

1. Adiabatic cooling - also orographic lifting by mountain range or convection (rising air, decrease in pressure --\> decrease in temperature) 2. Frontal systems - mixing of two air masses with different temperature; warm moist air rises 3. Contact cooling - moist air flows over cool surface -\> fog 4. Radiative cooling - at night: surface cooling by negative radiation balance -\> dew, frost, cooling of air and build up of radiative fog

Answer 51

- air temperature below dew point - water vapor content bigger than max. cap of atmosphere - surplus of water vapor is condensed around small airborne particles (condensation nuclei)

Answer 52

- hygroscopic particals having affinity for water vapor (mainly ocean salt particles) - non-hygroscopic particle: attracting condensation after some degree of super saturation, depending on size

Answer 53

clouds are formed --\> growth depends on hygroscopic and surface tension forces, humidity of air...

Answer 54

- Bergeron- Findeisen process - Growth by collision - Growth by accretion

Answer 55

T \< 0°C mixed cloud (droplets & ice particles) water vapor deposits on the ice particles air becomes unsaturated with respect to water, droplets evaporate crystals grow at the expense of droplets

Answer 56

T \> 0°C no ice larger droplets fall faster than smaller ones they collide and coalesce --\> grow maritime clouds --\> T high, water vapor amount: high

Answer 57

mix of droplets and ice particles snow/hail is formed as droplets fuse on to ice particles takes place in same type of cloud that favors the Bergeron process --\> except large amout of liquid water is necessary for collision

Answer 58

fake nuclei (dry ice)

Answer 59

High clouds (10km): Cirrus (ice crystals) ``` Middle clouds (5km): Alto- (water droplets or ice crystals) (Altocumulus, Altostratus) ``` ``` Low clouds (2 km): Mainly with waterdroplets (Cumulus, Cumulonimbus, Nimbostratus) ``` | (Cirrocumulus, Cirrostratus)

Answer 60

* Orographic rainfall * Convective precipitation * Cyclonic precipitation * Monsoon (ITCZ intertropical convergence zone) * Waves in the Easterlies

Answer 61

Maritime air mass over land air is heated --\> rise by convection - deep cumulus clouds are formed - many parts of tropics --\> strong rainfall

Answer 62

Boundary between two air masses

Answer 63

Sunny intervals, possibly showers

Answer 64

Bursts of heavy rain, Possible Thunder

Answer 65

Sunny intervals, increasing cloud

Answer 66

Sunny, warm and humid

Answer 67

Dull with more continuous moderate rain

Answer 68

Cloudy with light rain and drizzle

Answer 69

Bright, some watery sunshine

Answer 70

Divergence and Convergence

Answer 71

- Small disturbance in the trade winds 5- 25 ° N / S - Heavy rainfall possible - Low pressure may deepen to form hurricanes, cyclones

Answer 72

* Weather pattern of seasonal nature * changes in atmospheric pressure --\> movements of the ITC

Answer 73

ET variability can be as high as 20% in a field Issues to measure surface temperature

Answer 74

**Micrometeorological approaches** eddy covariance energy balance **physiological approaches** sap flow dendrometer **hydrological approaches** evaporation balance soil water measurement **lysimeter** **remote sensing** determination of the NDVI (normalized differnece vegetation index) **models** ``` statistical approaches (Haude, Dalton) simple physical approaches (Penman - Monteith) ```

Answer 75

Wildsche Waage (Wild evaporimeter scale) Piche Evaporimeter

Answer 76

Weighable Lysimeter

Answer 77

Controls the water loss from plant leaves

Answer 78

Tensiometer

Answer 79

single plant --\> small lysimeter (weight of potted plant) plant community --\> Big Lysimeter Water surface --\> Evaporation tanks Soil area --\> Water content Natural canopy --\> Micrometeorological approaches Landscape --\> Water balance Continent, globe --\> Water balance

Answer 80

determine potential evapotranspiration with: air temperature vapour pressure (e) additional factor for season and crop

Answer 81

simple physical -empirical approach to determine potential evaporation includes wind function radiotaion balance saturaltion vapour pressure deficit

Answer 82

includes the effect that plants can regulate their transpiration by stromata closure or opening canopy resistance (stomata resistance introduced) --\> method is practical for calculating the actual evapotranspiration

Answer 83

In the Penman - Monteith approach the surface temperature is assumed as the air temperature --\> Measure surface temperature --\> apply correction --\> Evapotranspiration can reach 20% in a field

Answer 84

Given: Surfce area of lysimeter lysimeter mass before and afterwards Precipitation durch measurement interval Meassured infiltrated water Measured surface runoff --\> Actual evaporation (evapotranspiration) during time t

Answer 85

Water balance equation Many years --\> Storage is neglectable --\> ETR can be calculated with Precipitaation and Runoff

Answer 86

Bowen ratio sensible heat flux / latent heat flux

Answer 87

Precipitation = Evapotranspiration + delta soil water + percolation p (precipitation) : Measured with rain gauge aside Delta soil water: Measured either by weighing or separated soil moisture measurements

Answer 88

Graph shows beginnig and end of growth periods... Rainfall... Dry periods

Answer 89

Measures temperature in "Sapwood" part of tree

Answer 90

Water beneath the surface in the saturated zone (saturated kommt unter unsaturated) Groundwater greatly affected by evapotranspiration and interaction with surface water Water table: Surface of saturation

Answer 91

unit of land on which all water that falls collects by gravity and runs out via a common outlet

Answer 92

Climatic factors (precipitation vs. evapotranspiration) Catchment factors: total area slope soil rock type Meteorological factors (rainfall intensity) Catchment factors Human factors (hydraulic structures, agricultural techniques, urbanization)

Answer 93

- Spacial variability - Seasonal variability (regime of the river)

Answer 94

Streamflow moderators

Answer 95

Moves water as a resource and a habitat more into the centre of policy making

Answer 96

Laser beam --\> Raindrops --\> fall velocity can be derived Problems: Wind speed Masking effect Margin fallers Technical problems Birds, pollen, insects, spider webs

Answer 97

Terminology: Virtually certain to Exceptionaly unlikely

Answer 98

water vapor: greenhouse effect 62% Co₂: 22% 0₃: 7%

Answer 99

More fossil fuel burning --\> more decomposition over the ocean --\> ocean gets more acid

Answer 100

Co2 in oceans also increasing, pH lowering Different isotopic signature of fossil fuel buring Falling levels of O2 in the atmosphere Amount of CO2 emitted known

Answer 101

As the ocean warms up, the water expands (bigger effect than additional water) Melting of glaciers, ice caps

Answer 102

Detection: Is change statistically significantly different from what can be explained by internal variability? Attriution: unlikely to be due entirely to internal variability

Answer 103

Precipitation Measurement counting drops through laser iode

Answer 104

Precipitation measurement funnel --\> channels precipitation into container --\> after enough water is collected --\> dumped --\> electrical signal sent Not that accurate --\> tends to underestimate the amount of rainfall

Answer 105

Doesnt work well with snow Would need electricity to melt snow --\> weighing bucket gauge?

Answer 106

Estimating mean precipitation accross an area by drawing lines of equal precipitation / topographic lines

Answer 107

For regions were orographic precipitaion is important

Answer 108

potential evaporation cylinder with a diamerter of 120 cm. Daily evaporation is measured pan is filled up to exactly 5 cm.. After 2 hours the amount needed to refill the pan is measured

Answer 109

Measures the amount of water that infiltrated into the soil Soil is weighted, perculation is considered and then compared to the actual perculation transpiration can be calculated good for farm crops, difficult for forests ONLY INSTRUMENT THAT MEASURES ACTUAL EVAPOTRANSPIRATION

Answer 110

Measures soil moisture burry in soil handpump --\> partial vacuum Water added to the soil --\> Vacuum inside the tube pulls moisture from the soil and decreases

Answer 111

evaporation (wet and dry bulb thermometer) - measures the water vapor in air - like hygrometer: dry bulb measures temperature and wet bulb measures temperature: difference --\> relative humidity

Answer 112

measuring the water vapor in the atmosphere

Answer 113

An instrument for measuring the area of stromatal openings of a leaf by amoutn of gas passing through (--\> control of the water loss of a plant)

Answer 114

evaporation graduated tube, closed at one end, filled with destilled water. covered with piece of filter paper. Amount of evaporation --\> change in level of meniscus of water

Answer 115

Evaporation a bowl filled with water... measurement can be directly read from scale

Answer 116

precipitation counts the drops falling though a laser beam measures the size, no of drops, diameter --\> reports the no. of drops with a specific diameter and their velocity

Answer 117

For the estimation of circumference of a tree stem and the size of a tree --\> diameter variance of a tree indicates water stress

Answer 118

Disadvantage: Water loss through evaporation, leaves/dirt blocking system

Answer 119

Measures ratio of increase in temperature following the release of a pulse of heat downstream (blue) and upstream (blue) from heater (red) --\> direction of water flux can be calculated

Answer 120

Measures the wind speed

Answer 121

measures wind speed and direction

Answer 122

To see the height of e.g. a river Convert into discharge, also measuring velocity of the river Water level at gauge station