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Abstract. Hauchecorne and Chanin ( 1980 ) developed a robust method to calculate middle-atmospheretemperature profiles using measurements from Rayleigh-scatter lidars. Thistraditional method has been successfully used to greatly improve ourunderstanding of middle-atmospheric dynamics, but the method has someshortcomings regarding the calculation of systematic uncertainties and thevertical resolution of the retrieval. Sica and Haefele ( 2015 ) have shown that theoptimal estimation method (OEM) addresses these shortcomings and allowstemperatures to be retrieved with confidence over a greater range of heightsthan the traditional method. We have calculated a temperature climatologyfrom 519 nights of Purple Crow Lidar Rayleigh-scatter measurements using anOEM. Our OEM retrieval is a first-principle retrieval in which the forwardmodel is the lidar equation and the measurements are the level-0 countreturns. It includes a quantitative determination of the top altitude of theretrieved temperature profiles, the evaluation of nine systematic plus randomuncertainties, and the vertical resolution of the retrieval on aprofile-by-profile basis. Our OEM retrieval allows for the verticalresolution to vary with height, extending the retrieval in altitude 5 to10 km higher than the traditional method. It also allows the comparison ofthe traditional method's sensitivity to two in-principle equivalent methodsof specifying the seed pressure: using a model pressure seed versus using amodel temperature combined with the lidar's density measurement to calculatethe seed pressure. We found that the seed pressure method is superior tousing a model temperature combined with the lidar-derived density. Theincreased altitude capability of our OEM retrievals allows for a comparisonof the Rayleigh-scatter lidar temperatures throughout the entire altituderange of the sodium lidar temperature measurements. Our OEM-derived Rayleightemperatures are shown to have improved agreement relative to our previouscomparisons using the traditional method, and the agreement of theOEM-derived temperatures is the same as the agreement between existing sodiumlidar temperature climatologies. This detailed study of the calculation ofthe new Purple Crow Lidar temperature climatology using the OEM establishesthat it is both highly advantageous and practical to reprocess existingRayleigh-scatter lidar measurements that cover long time periods, duringwhich time the lidar may have undergone several significant equipmentupgrades, while gaining an upper limit to useful temperature retrievalsequivalent to an order of magnitude increase in power-aperture product due tothe use of an OEM.

Improvements to a long-term Rayleigh-scatter lidar temperature climatology by using an optimal estimation method