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Click to edit Master subtitle styleKelembaban Udara

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Applied Meteorology for betterlife

Mark Twain (1835-1910)

Everybody talks about

the weatherBut nobody does

anything about it

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Siklus hidrologi Pernyataan kelembaban udara

Pengukuran kelembaban udara Kelembaban udara di permukaan Kenyamanan

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Soal latihan Mengapa atmosfer punya 2 lapisan

inversi? Suhu rata-rata di Jakarta (0 mdpl)

adalah 29 0C. Jika tiap kenaikan100m suhu udara turun 0,61 C0maka berapa suhu udara Puncak Pas

(1200 m dpl)?

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Contoh soalKota mdpl Lintang Bujur Kode Lokasi

Akzhar, Kazakhstan 365450 57

LU770 14 BT

Perth, Australia 20310 56

LS

1150 58

BT

Wellington, NewZealand

128 410 17LS

1740 46BT

Amsterdam,

Netherlands2

520 18

LU040 46 BT

Mecca, Saudi Arabia 161210 29

LU390 50 BT

Kode Jan Feb Mar Apr Mei Jun Jul Agu Sep Okt Nov Des Rataan

A 17 16 16 13 11 10 8 9 10 11 13 15 12B 24 24 22 18 16 13 12 13 14 16 18 21 18C -12 -2 -1 9 15 21 23 21 15 6 -2 -10 6D 23 24 27 31 34 35 35 35 35 32 28 25 31E 3 2 6 8 12 15 16 16 14 10 6 4 10

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Hydrology cycle

This cycle of moving and transforming water molecules from liquid tovapor and back to liquid again is called the hydrologic (water) cycle.

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Tekanan uap air(vapor pressure) Suhu titik embun

(dew point) Relative humidity Saturation deficit Mixing ratio, r (g/Kg) Vapor pressure deficit

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Pernyataankelembaban

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Pernyataan KelembabanUdara

Tekanan uap air

1010

es = 6.1078 x e(17.239T/(T + 237.3))

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ernya aanKelembaban UdaraRelative Humidity The ratio of the airs vapour pressure

(e) to the saturated vapour pressureat the airs temperature e ,expressed as a percentage

the ratio of the water actually present in the air to the maximum

amount that could be present at theairs temperature

a poor index of the amount of

moisture in the atmosphere, because

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UdaraRelative Humidity: Desert air VsPolar Air Higher RH?

Higher water vapor?

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ernya aan e em a anUdara

Mixing ratio, r (g/Kg) the ratio of the mass of water vapourin a unit mass of air (excluding thevapour)

advantage : remaining unalteredwhen a parcel of air rises or falls inthe atmosphere, so long as there is

no evaporation or condensation.r = mv/md

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Definisi :Mixing ratio, r (g/Kg)

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Pernyataan KelembabanUdara Vapor pressure deficit Kerapatan uap air =mv/V dewpoint

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Pengukuran KelembabanUdara

Psychrometer Wet-bulb depression

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Tabel estimasi nilai suhu titik embun

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Tabel estimasi nilai kelembaban relatif

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Humidity at surface depends on:

the latitude proximity to the sea Elevation the season time of day urbanisation

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Humidity at surface:increasing latitude Increasing latitude is associated with

lower vapour pressures

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Humidity at surface:Distance from the Ocean Vapour pressures are increased by

evaporation from nearby warmoceans

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Humidity at surface:elevation

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Humidity at surface:season

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Humidity at surface:daily variation

?

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Humidity at surface:daily variation

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Sebaran Kelembaban Nisbi menurut Waktu

RH lebih tinggi pada malam hari dibandingkan siang hari, karenatekanan uap jenuh semakin tinggi dengan naiknya suhu udarasedangkan tekanan uap aktual relatif tetap pada siang maupun malam.

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Humidity at surface:city Vs sub-urban

?

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HUMIDITY AND HUMAN COMFORT

21-22 C 24-25 C Clothing,

wind,radiation andhumidity

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Contoh soal

Pada suhu 28,4 0C RH=80%Pada suhu 15,5 0C RH=90%

Mana yang mengandung uap air

T

es(mb

.111 .111

.11 11

.1111

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Contoh soal B-S Kelembaban udara relatif pada suhu

titik embun adalah 100% Selisih antara 30 0C dan 250C adalah

90F Permukaan daratan dan lautan

mempunyai respon yang tidakberbeda terhadap radiasi matahariyang datang

Semakin besar perbedaan suhu bola

basah dengan suhu bola kering pada

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Manakah yang paling cepatberkondensasi

a. RH 70%b. RH 90%c. Vpd =0,15 esd. ea=0.91 es

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A li d M l f b