Meteorology 5 03 Moisture References FTGU pages 135
- Slides: 30
Meteorology 5. 03 Moisture References: FTGU pages 135 -138, 146 -147
5. 03 Moisture • MTPs: – Humidity – Changes of State – Dew and Frost – Cloud Formation – Precipitation – ICAO Lapse Rates – Inversion and Isothermals
Humidity • Relative Humidity – Ratio of water present in air compared to the amount the same volume could hold if it were saturated • Dew Point – Temperature to which air must be cooled at constant pressure to become saturated
Humidity • The warmer the air, the more water vapour it can hold. . . Why? 1 kg air at 0 degrees = 5 g water 1 kg air at 30 degrees = 30 g water
Humidity • Example – If we took a parcel of air at 10 o. C at 100% relative humidity and warmed it up, how would the relative humidity change?
Confirmation • Define Relative Humidity • Define Dew Point
Changes of State • • • Freezing Evaporation Melting Sublimation Condensation
Changes of State
Confirmation 1. What do you call a change of state from liquid to solid? 2. From solid to gas? 3. From vapour to liquid?
Dew and Frost • Dew and Frost form on clear, still nights • Vegetation and other objects cool by radiation below the dewpoint • If the dewpoint is above freezing, dew will form by condensation • If the dewpoint is below freezing, frost will form by sublimation
Cloud Formation • Invisible water vapour becomes visible as water droplets or ice • Condensation of water vapour
Cloud Formation • What is required: – High relative humidity – Condensation nuclei – Cooling of the air • Cold surface • Adiabatic cooling
Cloud Formation • Steps – Air is heated and rises – Air cools to point of saturation – Air condenses onto condensation nuclei
Confirmation • What are three things required for cloud formation?
Precipitation • Water droplets grow in size and weight and fall due to gravity – Can also occur below freezing (water vapour and ice crystals) The average rain drop is a million times larger than a cloud water droplet
Precipitation If the cloud is…. . • Below freezing – joining of ice crystals • Above freezing = rain • If temp below is cold enough to allow crystals to fall to ground = snow
Precipitation • Regions of a cloud • Snow • Rain and/or snow • Rain • Large drops and heavy rain = strong vertical motion
Precipitation Types of precipitation • Drizzle – very small drops of water which appears to float • Rain – Large water droplets
Precipitation • Hail – Hard transparent layer of ice covering soft white core • Snow Grains – Tiny snow crystals that have acquired a coating of rime
Precipitation • Snow Pellets – Soft white ice (hail without hard transparent layer • Snow – Agglomeration of ice crystals hexagonal/star shaped
Precipitation • Ice Prisms Tiny ice crystals in the form of needles • Ice Pellets Formed by freezing of raindrops
Confirmation • What are the 8 different types or precipitation?
ICAO Lapse Rates • Lapse rate – Rate of decrease in temperature with altitude
ICAO Lapse Rate • Lapse rates: Dry Adiabatic 3. 0 °C / 1000 ft Saturated Adiabatic 1. 5° C / 1000 ft Standard 2. 0 °C / 1000 ft ICAO 1. 98 °C / 1000 ft • Recall ICAO Standard Atmosphere: Air is perfectly dry gas Mean sea level pressure of 29. 92 Mean sea level temp of 15°C
ICAO Lapse Rates • Can determine base of clouds: – – Temperature on ground 10 degrees Dew point 7 degrees Lapse Rate Dry Adiabatic (3°C/1000 ft) Cloud base = 1000 feet
Inversion and Isothermals • There are exceptions to standard lapse rates • Inversion – Increase in temperature with altitude • Isothermal Layer – Layer in which temperature remains the same • Both these conditions produce stability. More on this in 5. 05
Confirmation 1. What is the dry adiabatic lapse rate? – _____ degrees per _____feet 2. What is hail? 3. A parcel of air has a relative humidity of 50%. If the temperature were to decrease how would the relative humidity change?
Rain on the Beach
- Printed pages vs web pages
- Moisture mapping software
- Shea moisture revenue
- Define equilibrium moisture content
- Stand over
- Chapter 36 moisture control
- Moisture and total solids analysis
- Chapter 18 moisture clouds and precipitation
- Bonide leaf shine and moisture guard
- Estimating soil moisture by feel and appearance
- Kinesis animal behavior
- Sentek soil moisture
- Egyptian gods height
- Resistive soil moisture sensor working principle
- Wisemini desiccant
- Localized convective lifting examples
- Falling rate period of drying formula
- Lab 5 atmospheric moisture
- "concrete curing"
- Tanya hoogerwerf
- Moisture equation
- Grain moisture content measurement
- Soil moisture introduction
- Soil moisture meter argos
- Intermediate moisture meat
- Soil moisture sensor
- Infiltration indices
- Moisture holding capacity
- Surface moisture content formula
- Cotton roll isolation
- Moisture sorption isotherm