====== Atmospheric Emitted Radiance Interferometer (AERI)  ======

{{:wiki:instruments:aeri01.jpg?direct&400|AERI at JOYCE ©B. Pospichal}} \\
//AERI installed at Jülich//

===== Principle =====
The AERI is an operational infrared spectrometer that measures the downwelling infrared radiance from 3.3-19 µm at 1 cm<sup>-1</sup> resolution. Like the microwave spectrum, the infrared spectrum also contains information on the vertical profile of temperature and humidity. Spectral observations from 612-713 cm<sup>-1</sup> and 2223-2260 cm<sup>-1</sup> (i.e., measurements from the 15 µm and 4.3 µm CO2 bands, respectively) are used for temperature profiling, and observations from 538-588 cm<sup>-1</sup> and 1250-1350 cm<sup>-1</sup> (i.e., measurements from the wings of the rotational and 6.3 µm water vapor bands, respectively) for water vapor profiling. Additionally, selected window channels provide information on low-LWP (< 50 gm<sup>-2</sup>) liquid water cloud effective radius and cloud optical depth as well as ice clouds and aerosol. Currently, our AERI is also used for columnar trace gas retrieval (CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>O). 


===== Measurement modes =====

  * Vertically pointing observations of downwelling spectral radiance in two spectral bands 
  * Band 1: 520-1800 cm<sup>-1</sup> (5.6-19.2 µm)
  * Band 2: 1800-3020 cm<sup>-1</sup> (3.3-5.6 µm)


===== JOYCE-CF Standard Operation Procedures =====

  * Radiances in both spectral bands with a temporal resolution of 20 seconds and a spectral resolution of 1 cm<sup>-1</sup>
  * [[https://www.arm.gov/capabilities/vaps/aerioe|AERI-OE profiles]] using an optimal estimation framework to derive cloud and thermodynamic (temperature, water vapor) profiles using AERI radiances and additional inputs. More information can be found in [[https://doi.org/10.1175/JAMC-D-13-0126.1|Turner and Löhnert 2014
]]
===== Data availability =====

Data are available on request, please fill the {{ :joyce_data_request_form.pdf |data request sheet}} and send it to [[mailto:info@joyce.cloud|info@joyce.cloud]].

 
^ Dataset     ^ Temporal resolution       ^ File size          ^ Filename   ^ Remarks   ^ 
| Downwelling radiances Channel 1  | 20 seconds    | 1 file per day (~39 MB)     | //jueaerich1C1.b1.YYYYMMDD.HHMMSS.cdf//  | NetCDF format   |
| Downwelling radiances Channel 2  | 20 seconds    | 1 file per day (~37 MB)     | //jueaerich1C1.b1.YYYYMMDD.HHMMSS.cdf//  | NetCDF format   |
| AERI-OE profiles (temperature, water vapor, cloud properties)   | 10 minutes    | 1 file per day (20-25 MB)     | //jueaerioe1turnC1.b1.YYYYMMDD.HHMMSS.cdf//  |  |






===== Link to current observations =====

Data quicklooks can be found in the [[http://atmos.meteo.uni-koeln.de/~hatpro/dataBrowser/dataBrowser4.html?site=JOYCE&date=-1&UpperLeft=AERI_spectrum1&UpperRight=AERI_status&LowerRight=AERI_rh_dewpt&LowerLeft=AERI_temp_wvmr|JOYCE quicklook browser]].

[[http://webmads.ssec.wisc.edu| AERI on webmads link]]: This link shows the current observation of AERI instruments around the world 

===== Measurement examples =====

Current observations:

{{http://gop.meteo.uni-koeln.de/~hatpro/jue/aeri/AERI_jue_1.png?nocache&w=600}} \\




===== AERI History =====
^  Period  ^  Place  ^  Project  ^
| May 13, 2011 - today  | Forschungszentrum Jülich | JOYCE |





===== Technical Specifications =====
^  Parameter  ^  Specification  ^  Remark  ^
|Spectral range receiver 1 | 5.6-19 µm | corresponds to 1800 to 520 cm<sup>-1</sup> |
|Spectral range receiver 2 | 3.3-5.6 µm | corresponds to 3020 to 1800 cm<sup>-1</sup> |
|Spectral resolution | 1 cm<sup>-1</sup> |  |
|Number of channels | ~2500 per receiver|  |
|Front end | gold-coated mirror, optical paths redirect radiation into back end |  |
|Calibration targets | 2 black bodies (ambient and hot load) | 3rd target optional  |
|Back end | FT-IR (Fourier Transform Infrared) spectrometer (ABB) |  |
|Temporal resolution | ~1 min for one spectrum | 142 interferometer sweeps / min.  |
|Manufacturer | ABB Analytical Business, Québec, CANADA |   |