Meteorology

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Meteorology (気象学)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Applications

Weather forecasting
Biological meteorology (生物気象学)

Agricultural meteorology (agrometeorology , 農業気象学): one of the branches of meteorology dealing with the relationship of weather and climate to crop and livestock production and soil management

seasonal forecast (half year, 3 months or 1 month)
weekly forecast (week)

Hydrometeorology
Maritime meteorology, etc.

Spatial representativeness (空間代表性)

the degree to which a measurement or sample reflects the characteristics of an area (or volume)

Atmospheric monitoring stations: a point measurement is representative if the probability that the squared difference between the point and area measurement is smaller than a certain threshold, e.g., 90%, of the time.

[ climatology | disaster ]

an eclispe seen at
Sapporo on October 8 2014

[ ultraviolet ]

Solar radiation or insolation (日射)

energy input → changing with latitudes and seasons

Energy balance

R_n = H + I_E + G + (A_in - A_out) + ΔSt + ΔP

S_t = ∫_Z₁^z₂[∂(Σ_iρ_ic_iT_i/∂t]dz + ∫_Z₁^z₂[∂(ρ_alq)/∂t]dz

➔ H: sensible heat flux

heats air
eddy transport ≫ thermal conduction

➔ I_E: latent heat flux

evapotranspiration
eddy transport

➔ G: ground heat flux

heats ground, melts snow and ice
thermal conduction

Temperature (温度)

Wind-chill factor (体感温度)

= wind chill or windchill
Def. Lowering body temperature by the passing-flow of lower-temperature air

a surface loses heat through conduction, evaporation, convection and radiation

Missenard equation (1937), M, °F = t - 1/2.3·(t - 10)·(0.8 - y/100)

t = air temperature, °C
v = wind velocity, m/s
h = relative humidity (%)

Linke equation, L = t - 4√v
Wind chill index, WCI = (10√v - v + 10.5)·(33 - t)

Def. discomfort index (不快指数), DI: combination of temperature and humidity that is a measure of the degree of discomfort experienced by an individual
= temperature-humidity index (温湿指数), THI

DI = 0.99t + 0.36t' + 41.5 or
DI = 0.81t + 0.01h·(0.99t - 14.3) + 46.3

t' = dew-point temperature

Atmosphere (大気)

Def. A layer of gases that envelop an astronomical object and is held in place by the gravity of the object

Air pressure (pressure, 気圧)

Def. force per unit area exerted by an atmospheric column (that is, the entire body of air above the specified area)

Barometer (気圧計)

Ex. aneroid barometer, Fortin barometer (フォルタン型水銀気圧計)
Def. Reduction (of pressure) to mean sea level (海面更正)

adjusting atmospheric pressure at various altitudes to a common reference level, i.e., sea level

Sea level pressure (SLP, 海面気圧), ΔP

= mean-sea-level barometric pressure (海面更正気圧)

ΔP = P₀ - P = P(exp(gh/RT_m) - 1)

P₀: pressure at sea level
P: pressure at the observed point
g: acceleration of gravity
h: altitude above sea level at the observed point
R: gas constant of air
T_m: the average virtual temperature from sea level to h m expressed in absolute temperature

Wind direction, force and velocity (風向・風力・風速)

Wind direction

Wind force

Beaufort scale of wind force (ビューフォート風力階級)
an empirical measure showing wind speed (at 10 m above the sea surface) to observed conditions

Ex. Beaufort number. description: wind speed, kt/m·s^-1 (wave height, m): sea conditions; land conditions

Calm (静穏): < 1/0.5 (0);
sea like a mirror
smoke rises vertically
Light air (至軽風): 1-3/0.5-1.5 (0-0.3):
ripples with appearance of scales are formed, without foam crests
direction shown by smoke drift but not by wind vanes
Light breeze (軽風): 4-6/1.6-3.3 (0.3-0.6)
small wavelets still short but more pronounced; crests have a glassy appearance but do not break
wind felt on face; leaves rustle; wind vane moved by wind
Gentle breeze (軟風): 7-10/3.4-5.5 (0.6-1.2)
large wavelets; crests begin to break; foam of glassy appearance; perhaps scattered white horses
leaves and small twigs in constant motion; light flags extended
Moderate breeze (和風): 11-16/5.5-7.9 (1-2)
small waves becoming longer; fairly frequent white horses
raises dust and loose paper; small branches moved
Fresh breeze (疾風): 17-21/8-10.7 (2-3)
moderate waves taking a more pronounced long form; many white horses are formed; chance of some spray
small trees in leaf begin to sway; crested wavelets form on inland waters
Strong breeze (雄風): 22-27/10.8-13.8 (3-4)
large waves begin to form; the white foam crests are more extensive everywhere; probably some spray
large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty
High wind, moderate gale, near gale (強風): 28-33/13.9-17.1 (4-5.5)
sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind; spindrift begins to be seen
whole trees in motion; inconvenience felt when walking against the wind
Gale, fresh gale (疾強風): 34-40/17.2-20.7 (5.5-7.5)
moderately high waves of greater length; edges of crests break into spindrift; foam is blown in well-marked streaks along the direction of the wind
twigs break off trees; generally impedes progress
Strong/severe gale (大強風): 41-47/20.8-24.4 (7-10)
high waves; dense streaks of foam along the direction of the wind; sea begins to roll; spray affects visibility
slight structural damage (chimney pots and slates removed)

wind
Fig. Compass rose
(meteorological compass)

Storm, whole gale (暴風): 48-55/24.5-28.4 (9/12.5)
very high waves with long overhanging crests; resulting foam in great patches is blown in dense white streaks along the direction of the wind; on the whole the surface of the sea takes on a white appearance; rolling of the sea becomes heavy; visibility affected
seldom experienced inland; trees uprooted; considerable structural damage
Violent storm (烈風): 56-63/28.5-32.6 (11.5-16)
exceptionally high waves; small- and medium-sized ships might be for a long time lost to view behind the waves; sea is covered with long white patches of foam; everywhere the edges of the wave crests are blown into foam; visibility affected
very rarely experienced; accompanied by widespread damage
Hurricane force (颶風): ≥64/≥32.7 (≥14)
the air is filled with foam and spray; sea is completely white with driving spray; visibility very seriously affected
devastation

*: wind speed codes are somehow different between regions or research subjects. The units (単位) are also different.

Wind direction (風向)

Fig. Connection of Beaufort force, Fujita scale and Mach number.

V = 1.8708^1.5 mpg = 0.836B^{1.5^m/s}
V = 141(F + 2)^1.5 mph = 6.30 (F + 2)^1.5 m/s
V = (742 + 1.3t)M mph = (331 + 0.6t)M m/s

Wind velocity

Terminology:
Instantaneous (momentary) wind speed (velocity) (瞬間風速)

→ maximum instantenious wind or peak gust (最大瞬間風速)

Maximum sustained wind, maximum wind speed (最大風速)

Low (atmospheric) pressure, L(A)P (低気圧)

Law. Buys Ballot's law (Buys Ballot CHD 1857)
If one stands with one's back to the wind, in the Northern (Southern) Hemisphere the atmospheric pressure will be lower on one's left (right) Terminology:
northerly/easterly/southerly/westerly (北/東/南/西風方向)
southwestward (南西方向)

Cloud (雲)

Def. A visible mass of liquid droplets or frozen crystals made of water or various chemicals suspended in the atmosphere (→ aerosols) above the surface of a planetary body

Cloud classification

cirro-: curl of hair, high
alto-: mid
strato-: layer
nimbo-: rain, precipitation
cumulo-: heap

Aerosol (エアロゾル)

Natural aerosol = cloud, volcanic ash, (fire smoke - sometimes anthropogenic), etc. Anthropogenic aerosol = factory emission, veichle exhaust, etc.
ENSO → El niño, inducing severe wildfire (in southeastern Asia)

Aerosol optical thickness (AOT) or depth (ADT)

☛ Black carbon (ブラックカーボン)

Precipitation (降水)

Def. Humidity (湿度), V: the amount of water vapor present in the air

absolute humidity + relative humidity + specific humidity

Def. absolute humidity (絶対湿度): the total mass of water vapor per unit volume of air, often expressed in g/m³
Def. relative humidity, RH (相対湿度, %): the ratio of the current amount of water vapor in the air to the maximum amount it can hold at a given temperature
Def. specific humidity (比湿): the mass of water vapor per unit mass of air, including both dry air and water vapor, often measured in g/kg

Pan evaporation (計器蒸発量)

A measurement that combines or integrates the effects of several climatic elements, such as temperature, humidity, rain fall, drought dispersion, solar radiation and wind
pan

Application: agriculture - to know how much water the crops need

Weather (天気)

the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy

Synoptic meteorology (総観気象学)

geostationary meteorological satellite, GMS (静止気象衛星)

AMeDAS (アメダス)

= Automated Meteorological Data Acquisition System (probably Japanglish)

Research sites [ database ]

Sarobetsu Mire: 45°06N, 141°42E, 7 m a.s.l.
Toyotomi (豊富): 45°06.1'N, 141°46.8E, 14 m (7 km far from the post-mined peatland)

temperature, precipitation, snowfall, snow depth, sunshine hour, wind speed, wind direction

Horonobe (幌延): 45°00.4'N, 141°51.1'E, 5 m (13 km)

precipitation

Numakawa (沼川): 45°14.9'N, 141°51.1'E, 23 m (20 km)

temperature, precipitation, snowfall, snow depth, sunshine hour, wind speed, wind direction

Wakkanai (稚内): 45°24.9'N, 140°40.7'Ee, 2.8 m (> 30 km)

temperature, precipitation, snowfall, snow depth, sunshine hour, global solar radiation, wind speed, wind direction

Mount Usu: 42°30'N, 140°50'E, 727 m a.s.l.
Toya Spa (洞爺湖温泉): 42°39.9'N, 140°48.4E, 85 m

precipitation, snowfall, snow depth

Date (伊達): 42°28.5'N, 140°50.9'E, 3 m

temperature, precipitation, sunshine hour, wind speed, wind direction

Mount Koma: 42°03'N, 140°40'E, 1133 m a.s.l.
O-numa (大沼): 41°58.6'N, 140°42.9E, 165 m

precipitation, snowfall, snow depth

Mori (森): 42° 04.0'N, 140°35.3'E, 125 m

temperature, precipitation, snowfall, snow depth, sunshine hour, wind speed, wind direction

Screen (instrument screen, 百葉箱)

Forecast (天気予報)

the application of science and technology to predict the state of the atmosphere for a future time and a given location

Expression

settled weather (落ち着いた天気) ↔ hazardous or significant weather (悪天)