# IPC-XI Tutorial Pyrgeometer. Contents Pyrgeometer energy balance Equations for retrieving longwave irradiance Shaded versus unshaded pyrgeometers.

## Presentation on theme: "IPC-XI Tutorial Pyrgeometer. Contents Pyrgeometer energy balance Equations for retrieving longwave irradiance Shaded versus unshaded pyrgeometers."— Presentation transcript:

IPC-XI Tutorial Pyrgeometer

Pyrgeometer setup

Pyrgeometer energy balance Eppley PIR Kipp&Zonen CG4 5µm40µm20µm

Pyrgeometer energy balance Eppley PIR Kipp&Zonen CG4 Typical values: Net outgoing radiation ~ 100 Wm -2 PIR Dome (∆T=1K) ~18 Wm-2

Pyrgeometer equations Several choices for the radiometric model of a pyrgeometer: Simple Albrecht formula Extended Albrecht (PMOD) NREL formula Fit parameters

Calibration residuals versus WISG

Calibration residuals versus WISG results from 50 Instruments

Unshaded pyrgeometers NIGHT 1 Dome YSI

Unshaded pyrgeometers NIGHT NIGHT and DAY

Unshaded pyrgeometers Proxy: direct solar irradiance Proxy: Dome-body temperature 1 Dome YSI

Unshaded pyrgeometers PIR Dome proxy Direct irr proxy

Unshaded pyrgeometers PIR 3 Th. Dome proxy Direct irr proxy R=0.81 R=0.91 Effect is 6 W/m 2 per 1kW for this particular pyrgeometer 26955 3 dome

Unshaded pyrgeometers CG4 Effect is 5.5 W/m 2 per 1kW for this particular pyrgeometer cg4

Summary unshaded pyrgeometers InstrumentOffset per 1000 Wm -2 Direct irradiance PIR 3 Dome Thermistor7.0 PIR 3 Dome Th.6.2 PIR 3 Dome Th.6.8 PIR 3 Dome Th.7.4 PIR 1 Dome Th.11.2 PIR 1 Dome Th.15.3 PIR 1 Dome Th.11.5 PIR 1 Dome Th.4.0 PIR 1 Dome Th.8.5 PIR 1 Dome Th.11.4 PIR 1 Dome Th.4.6 InstrumentOffset per 1000 Wm -2 Direct irradiance CG42.6 CG45.4 CG43.1 CG4 CG45.3 CG45.5 CG113.4

Summary unshaded pyrgeometers InstrumentOffset per 1000 Wm -2 Direct irradiance PIR 3 Dome Thermistor7.0 PIR 3 Dome Th.6.2 PIR 3 Dome Th.6.8 PIR 3 Dome Th.7.4 PIR 1 Dome Th.11.2 PIR 1 Dome Th.15.3 PIR 1 Dome Th.11.5 PIR 1 Dome Th.4.0 PIR 1 Dome Th.8.5 PIR 1 Dome Th.11.4 PIR 1 Dome Th.4.6 InstrumentOffset per 1000 Wm -2 Direct irradiance CG42.6 CG45.4 CG43.1 CG4 CG45.3 CG45.5 CG113.4 Is there shortwave leakage in the solar blind filters?

IPC-XI Pyrgeometer intercomparison shaded unshaded Difference to WISG / Wm -2 PIR & CG4

IPC-XI Pyrgeometer intercomparison Difference to WISG / Wm -2 Only CG4