Types of Precipitation?
July 27, 2025
今日又溫下書…到底有咩類型既precipitation? 首先， what’s precipitation? 根據FAA PHAK chapter 12 (天氣果課書）： Precipitation refers to any type of water particles that form in the atmosphere and fall to the ground. 睇返之前 收集既一個wmo網頁，天氣現象大致分為：水、光、電、塵相關 Types of meteors (WMO) 而同水有關既可以睇呢個網： https://cloudatlas.wmo.int/en/hydrometeors.html Precipitation 係指 11類 falling particles (b) Falling particles (precipitation) 1. Rain : water droplets, but not drizzle
Change status of water
July 26, 2025
#Solid #liquid #gas #melting #evaporation #condensation #freezing #sublimation #deposition
點解會落雹 What’s hail?
July 26, 2025
話說琴晚黃昏就收到天文台特別天氣提示話會落雹可能，難道有冤情？ 🙂 都可能係 就係點解我仲未做到飛機師 因為我讀書未夠？ 咁就溫下書～ Hail is formed in strong thunderstorms when supercooled water droplets freeze onto ice pellets, which are then carried by powerful updrafts within the storm cloud. These ice pellets, or hailstones, grow larger as they repeatedly collide with more supercooled water droplets, eventually becoming too heavy to be supported by the updraft
Cloud formation: Bergeron-Findeisen theory (Icing) v.s Coalescence theory (Water droplet)
July 20, 2025
https://youtu.be/6WjU0kwu_ew?si=Kvf5LqleDUzpKo8b Cloud Formation
Cloud Formation
July 20, 2025
https://youtu.be/q87Ekar3emA?si=EN2zl3qUX1OmIcsh Read More https://www.britannica.com/video/process-cloud-formation-factors-surface-air-water/-203821 Cloud formation: Bergeron-Findeisen theory (Icing) v.s Coalescence theory (Water droplet) Cloud formation 夠竟係吸定放latent heat? Clouds 雲
Oktas – reporting the amount of cloud in the sky
July 20, 2025
https://worldweather.wmo.int/oktas.htm Oktas Definition Category 0 Sky clear Fine 1 1/8 of sky covered or less, but not zero Fine 2 2/8 of sky covered Fine 3 3/8 of sky covered Partly Cloudy 4 4/8 of sky covered Partly Cloudy 5 5/8 of sky covered Partly Cloudy 6 6/8 of sky covered Cloudy 7 7/8 of
點解ATIS 要點Temperature and Dew Point?
July 20, 2025
今日打風溫書…簡接溫故知新~ 下面有個ATIS 實例…有T 28 /DP 26 要推算Cloud Base = T-DP * 400 = (28-26)*400 = 2* 400 = 800 feet AGL 再反推Relative Humidity (RH) = 100 – (T-D) *5 = 100 – (28-26) * 5 = 100 – 10 = 90% 呢兩條Rule of thumb 係work 既~
Calculation of Freezing Height
July 20, 2025
The Bradbury Rule Example: OAT 10 degree C ; DP 7 degree C Calculate Cloud Base T – DP * 400 = (10-7) * 400 = 1200 feet AGL Calculate Freezing layer DP / 1.8 * 1000 = 7/1.8 * 1000 = 3889 feet AGL Freezing height 1200 + 3889 = 5089 feet AGL This
How to find the Dew Point? How to find Relative Humidity (RH)?
July 20, 2025
How to find the Dew Point? RH = 100 – (T-D) x 5 Example: RH 83% ; Temp 12C, then 83 = 100 – (12-D) x 5 (83-100) / (-5)= 12-D D = 12 – (83-100) / (-5) D = 8.6 degree C Rightly, we can interpret the relative humidity (find the RH) from
Dew Point Application – Calculate Cloud Base
July 20, 2025
Degree C Let’s say the temperature is 25°C and the dew point is 15°C. Convergence Rate (CR) = 2.5°C Temperature Dew Point Spread (TDS) = T-DP = 25 – 15 = 10°C TDS ÷ CR = 10 / 2.5 = 4 Multiply by 1000 = 4 * 1000 = 4000 feet Therefore, the estimated cloud
Dew point, Dew Point Spread
July 20, 2025
What’s Dew Point? Dew point, given in degrees, is the temperature at which the air can hold no more moisture. When the temperature of the air is reduced to the dew point, the air is completely saturated and moisture begins to condense out of the air in the form of fog, dew, frost, clouds, rain,
ISA Deviation
July 20, 2025
Example: FL290 ; OAT -47 degree C ISA standard = 15 – (feet /1000) * 2 ISA Deviation = OAT – ISA standard FL 290 : 29,000 feet, so ISA standard @ FL 290 = 15- (29*2) = -43 degree C ISA deviation = -47 – -(43) = ISA-4 degree C https://youtu.be/_oWqu12Dm6M?si=eUYvJoTQD_EOKKl2
Thermodynamics: Radiation, Conduction, Convection & Advection
July 20, 2025
https://youtu.be/0vdxlgRKx1k?si=a80FzWfEp2fsKj2K What’s Solar insolation?
Tropopause
July 20, 2025
What’s Tropopause? https://youtu.be/jTCWSjhhXgc?si=9Zf8eVJgx6TKOXDs Tropopause height and its significance? https://youtu.be/ZfGVHCJSDsw?si=qaqwuN4DSlX6uyiu https://youtu.be/dRI5gYrJmvo?si=NHQo3NtST_5f-9ei More Reference: https://code7700.com/tropopause.htm
Cloud formation 夠竟係吸定放latent heat?
September 14, 2024
https://www.weather.gov/source/zhu/ZHU_Training_Page/clouds/cloud_development/clouds.htm Formation of cloud requires a continuation of the lifting process. It is assisted by the property of water of giving off heat when changing from vapor to liquid and solid states, the latent heats of condensation and of deposition, respectively. (If the vapor first changes to a liquid before freezing, then we also have
Clouds 雲
September 8, 2024
Ref: https://cloudatlas.wmo.int/en/clouds.html 雲係一種同水有關既大氣現象 A cloud is a hydrometeor consisting of minute particles of liquid water or ice, or of both, suspended in the atmosphere and usually not touching the ground. It may also include larger particles of liquid water or ice, as well as non-aqueous liquid or solid particles such as those present in fumes, smoke or
Types of meteors (WMO)
September 8, 2024
Ref : https://cloudatlas.wmo.int/en/general-classification-of-meteors.html (4) Four types of meteors (WMO): 水 moisture related 光 light related 電 electrical related 塵 dust and particle related Meteors present a great diversity of character. However, by considering their constituent particles or the physical processes surrounding their occurrence, meteors can be classified into four groups: hydrometeors, lithometeors, photometeors and electrometeors. 大氣現象呈現出多種多樣的特徵。但是，根據它們的組成粒子或它們發生期間的物理過程，大氣現象可以分為四組：水凝物、大氣塵粒現象、大氣光學現象 和 大氣電學現象。
