Intro Atm. wk 2 Flashcards
currently only chapter 6 till page 74. still to do: p.75 and chapter 4&5
what does the KNMI measure
wind speed, temperature, moisture, and precipitation. (standard meteorological measurements)
what does the RIVM measure
air quality.
list basic variables measured by KNMI stations
air temperature, atmospheric pressure, humidityl depoint temp,wind speed and direction, precip, solar radiation, visibility, evaporaiton, soil moisture content, clouds, atmospheric composition, sea water temperature, waves and swell, lightining, boundary layer height.
what info do atmospheric research stations collect and what is their name?
the Ruisdael Observatory. These collect information on high spatila data and temporal surface and upper air observations.
where do we measure urban atmospheric measurements?
in rotterdam. emissions of GHGs, different land use.
Rdam specifically: port with petrochemicals, intense traffic and domestic heating, horticulture.
what is WMO
world meteorological organisation, part of UN
two european meteorological companies?
fluxnet, integrated carbon observation system.
two ways in which we measure meteo vertically?
radiosondes (weather balloon) and aircraft
how does a radiosonde work?
connected to helium balloon, they measure in 3D. Measure air pressure, temp and relative humidity.
how does aircraft help measure meteo
aircraft meteorological data relay (AMDAR) automates collection and transmission of weather forecasts made by commercial aircrafts. There are also light aircraft that fly to take measurements.
what are satellites useful for?
measuring radiation and looking at cloud patterns.
what do we use thermometres for?
measuring air temperature. they are made from platinum wire, defined resistance change with temperature. they are protected by a Stevenson screen, door towards the north, white on outside to have high albedo, and ventilation.
how do we measure air pressure
using a flexible vacuum chamber that is deformed by air pressure. we try to reduce the impact of dynamic pressure. s
what does a psychrometer measure?
air humidity by using a dry and wet bulb thermometer. (traditionally).
now, we use relative humidity sensors. this is a capacitor that can store charge.
what are anemometers used for?
measuring wind speed and direction.
there is a cup that rotates with wind speed. There is also an ultrasonic one which uses a sound pulse to measure wind speed.
what does a pyrheliometer measure
measures direct radioation from the sun
what does a pyranometer measure
shortwave radiation (global and diffuse)
what does a pyrradiometer measure
both short and longwave radiation.
what does a pyrgeometer measure
longwave radiation only.
what does a net-pyrradiometer measure
net radiation
how does a pyranometer work?
two glass domes with dark surface is warmed by solar radiation and heat flows. The temperature differencee can be used to measure radiation.
sensor is covered with a glass dome that is transparent for UV and visible. there is also an upside down sensor to measure reflection and therefore albedo.
how does a pyrheliometer work?
it is mounted on a sun tracker so it will always look at the sun. it has a narrow viewing window and can track sun hours.
what is the definition of sunshine
> = 120 Wm^-2
how is diffuse radiation measured
by a pyranometer that is shaded from direct sunlight only.
how does a pyrgeometer work?
with a thermopiile sensor byt it has a filter for solar radiaiton and transmits thermal radiation only. There is also one facing downward (2nd instrument in excursion)/
how are GHGs measured?
air is dried and measured using spectroscopy. (sometimes cavity ring down spectroscopy), based on absorption.
how do we measure eddy covariance fluxes
a fast 3d anemometer. Using radiation, flux measurements quantify surface energy balance. rising and descending air can be measured using IR and gas analyser.
how do we measure visibility
meteorological optical range. This is the greatest distance at which a black object (fixed size) can be seen on the ground. with visibility below 1km, you call it fog, 1-2km is mist, 2-5km is haze.
We measure this using light transmission and light scattering.
how do we measure precipitation?
we look at a tipping bucket, but also include snow, dew and hoarfrost.
what do we use a radar for and what are the two types?
we send a radio wave, which is reflected off a rain drop and then comes back. This tells you precip intensity. this is non-coherent radar
coherent radar also mesures the shift in frequency of the reflectee wave. It is more sensitive but therefore also measures pollen and insects by accident.
what is sodar used for?
reflected off of thermals and measures wind speed and direction.
what is a lidar used for
this is a laser that measures smaller particles eg. aerosols and pollution.
a ceilometer is a type fo lidar and measures tht e height of the boundary layer.
how do we measure particulate matter
it is separated by size either through mass or deposition. Light scattering is then measured.
how do we measure black carbon concentration?
using an aethalometer, which recognizes how much darker black carbon is compared to mineral particles.
how do we measure ammonia
using uv absorption bands.
what is passive sampling?
you have a Palmes tube and it has a metal at one end. the other end is open and the gas of interest flows in and reacts with the surface. therefore, less of the gas is in the tube and due to the concentration gradient, the gas flows in. you measure how much has reacted/
is there maths for the palmes tube?
yes unfortunately ….
when do you use active sampling
when there is not enough diffusion, instead you pump the air into the tube. But you have to be careful fo rcondensation and contamination.
what can geostationary satellites measure?
with mirrors, they turn and the radiation from a narrow point is measured through a focal point in the sensor. a small level of deformation occurs.
how about polar satellites?
they stay 800km away from earth, takes them a few hours to get around. but a different part is measured every orbit. they have passive sensors so they receive the radiation emitted by earth or the sun.
what is a sun synchronous orbit
when a polar satellite passes the same point twice a day.
what are the 3 types of meteo satellites?
VIS images, IR images, WV (water vapour) images
tell me about VIS images
radiaition intensity in the visible spectrum. both polar and geostationary satellites. teh shade is used to calculate albedo.
on what does cloud brightness depend
