Balloon-Borne Sounding System (BBSS)

• Used for atmospheric profiling• Measures P, T, RH, wind speed and

direction• Uncertainties arise from incorrect surface

conditions, humidity sensor saturation or icing, and interference and signal confusion from other radiosondes.

• An in situ measurement used for validation of remote sensers

Balloon-Borne Sounding System (BBSS)

Multifilter Rotating Shadowband Radiometer (MFRSR)

• Measures column ozone and water vapor

• Instrument takes spectral measurements of direct normal, diffuse horizontal, and total horizontal solar irradiances

• measurements taken every 20s (SGP site)

SODAR

• Measures profile of wind• Transmits a short pulse of sound which is refracted by

the small scale turbulence in the atmosphere. • radial velocity of the air can be determined by measuring

the Doppler shift of the sound being refracted from the turbulence.

• The range of the turbulence is determined from the delay between the transmission of the acoustic pulse, and the reception of the refracted signal

• http://www.wx.rutgers.edu/PAM/SODARdata.shtml

SODAR

Radio Wind Profiler (RWP)

• Measures wind and virtual temp profiles

• transmits electromagnetic energy into the atmosphere and measures the strength and frequency of backscattered energy

• Radio Acoustic Sounding System (RASS) at PAM site

• http://www.wx.rutgers.edu/PAM/RASSdata.shtml

1200

1000

800

600

400

200

3000 3010 3020 3030

MFRSR signal

t (s)

z (k

m)

0

0.5

1

1.5

2

0 5 10 15m/s

915 MHzwind profiler

x =t v chord length

cloud as viewed from below possible detected chord lengths

z (k

m)

W m-2

Estimating Cloud Scale

Barrow, AK

Lamont, OKManus, Papua New Guinea

Microwave Radiometer (MWR)

• provides time-series measurements of column-integrated water vapor and liquid water

• Measures microwave radiation at 23.8 and 31.4 GHz

• WV dominates the 23.8GHz channel

• Cloud liquid in the atmosphere dominates the 31.4 GHz frequency

Net Radiometer

• help determine the total energy exchange • provides measurements of shortwave (solar)

and longwave (atmospheric or infrared) irradiances for downwelling and upwelling components.

• DS = DNI*cos(Z)+DD• US = DS*ρ• DS ≤ETR• DNI ≤ETRN• IR = Ttp*C1+σTc

4-C2σ(Td4-Tc

4)

Net Radiometers

MicroPulse Lidar (MPL)

• optical remote sensing system designed

to determine the altitude of clouds overhead• Pulses of energy are transmitted into the

atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal

• time delay between each outgoing transmitted pulse and the backscattered signal used to infer the distance to the scatterer

Vaisala Ceilometer (VCEIL)

• ground-based, active, remote-sensing device designed to measure cloud-base height at up to three levels and potential backscatter signals by aerosols

• transmits near-infrared pulses of light, and the receiver telescope detects the light scattered back by clouds and precipitation

Millimeter-Wavelength Cloud Radar

• Determines cloud boundaries, radar reflectivity and vertical velocity

• transmitts a pulse of millimeter-wave energy from its transmitter through the antenna.

• energy propogates through the atmosphere until it hits objects that reflect some of the energy back to the MMCR (clouds, precipitation, insects, spider webs, etc.)

• received signal is split into two channels, termed I and Q (for in-phase and quadrature).

• Any radar’s sensitivity is proportional to the transmit power, the square of the antenna gain, and the square of the radar's wavelength. The sensitivity is inversely proportional to the square of the range from the radar to the target.

Websites

• http://apollo.lsc.vsc.edu/classes/met455/notes/section8/3.html