Title: Temperature and water vapor mixing ratio profiles retrieved from the AERI. Location: Minden, NE (PECAN Fixed PISA station #4) Lat/Lon: 40.515 degN, -98.951 degE Date updated: 15 August 2016 Contact: Dave Turner, NOAA (dave.turner@noaa.gov) --- Background The AERIoe algorithm (Turner and Loehnert 2014) retrieves profiles of temperature and water vapor mixing ratio, together with cloud properties for a single-layer cloud (i.e., LWP, effective radius), from AERI-observed infrared radiance spectrum. The data can be used to characterize the evolution of the planetary boundary layer and boundary layer clouds. This dataset was collected in Minden, Nebraska, which was the PECAN Fixed-PISA #4 site. The AERIoe retrieval was run at 5-minute resolution, but retrievals can be performed at the maximum temporal resolution of the AERI instrument (order 30 s) -- if this higher temporal resolution is desired, please contact Dave Turner. This is a physical-iterative retrieval method. The retrieval of thermodynamic profiles from spectral infrared radiance observations is an ill-posed problem, and thus constraints need to be included in the retrieval algorithm to provide physically plausible results. Here, we use a climatology of radiosonde profiles collected at the ARM SGP site during the summer as our prior information in an optimal estimation framework. As the method uses an optimal estimation framework, a full error covariance matrix of each solution is included in the output file. The 1-sigma uncertainty of each retrieved variable, which is derived from the error covariance matrix, is included for each scientific field and is named "sigma_X", where "X" is the name of the scientific field (e.g., 'temperature'). The information content in the AERI observations, which is in the "dfs" field, on the thermodynamic profiles is primarily concentrated in the lowest 3 km or up to cloud base; the retrieved data should not be used above that level (or used with caution). There is an overall "qc_flag" field that is set when a retrieval should not be trusted. However, the logic that sets this flag didn't work correctly, and it should not be used. Instead, consider all retrievals that have a value for "converged_flag" greater than 0 as valid. If you have any questions, contact Dave Turner. --- Version information This is Release_2_2 of the AERIoe algorithm. The main improvements over the previous version (Release_1_5) are: * Logic to prevent superadiabatic profiles above some minimum altitude * Inclusion of additional observations from surface met observations and the RAP weather forecast model above 4 km to better constrain the solution * Several minor bug fixes --- Details on the AERI The AERI (Atmospheric Emitted Radiance Interferometer) is a hardened, operational infrared spectrometer that was developed at the University of Wisconsin - Madison for the Department of Energy Atmospheric Radiation Measurement (ARM) program. Details of the AERI, including how it is calibrated, are provided by Knuteson et al. (2004 a,b). The ARM program provided the AERI instrument at Minden as part of the ARM-Support for PECAN (As-PECAN) experiment. The AERI instrument mentor team of Jon Gero and Denny Hackel at the University of Wisconsin - Madison deployed the AERIs during PECAN for the ARM program. The AERIoe retrievals were performed by Dave Turner. --- References Turner, D.D., and U. Loehnert, 2014: Information content and uncertainties in thermodynamic profiles and liquid cloud properties retrieved from the ground-based Atmospheric Emitted Radiance Interferometer (AERI). J. Appl. Meteor. Clim., 53, 752-771, doi:10.1175/JAMC-D-13-0126.1. Knuteson, R.O., and coauthors, 2004: Atmospheric Emitted Radiance Interferometer. Part 1: Instrument design. J. Atmos. Oceanic Technol., 21, 1763-1776. Knuteson, R.O., and coauthors, 2004: Atmospheric Emitted Radiance Interferometer. Part 2: Instrument performance. J. Atmos. Oceanic Technol., 21, 1777-1789. --- END