DOI: 10.18150/oaysao
title: Pollen lidar observations in Warsaw (2013-2021)

description: The dataset covers the period of 2013-2021 regarding the identified pollination cases observed with the multiwavelength aerosol polarization Raman lidar (PollyXT-UW) over the EARLINET-ACTRIS site in Warsaw, Poland (52.21° N, 20.98° E, 112 m a.s.l).Datasets were processed using resources of the Poland-AOD Data Server (http://www.polandaod.pl/). The cases of pollination events were identified on the basis of searching for a bell-like shape in 2-dim (time [UTC], Altitude [m a.s.l.]) quick-looks of the lidar range corrected elastic signals (Pr2) at 532 nm channels (total and polarized) form the PollyXT-UW lidar far-range transceiver. The background removal process was applied on each quick-look by selecting a rectangular sample of surrounding pixels (dimension of approximately 1 km over 24 h at high altitudes 7-12 km). For every identified pollination event with removed background, the values of volume depolarization ratio (VDR) lower than the background average were multiplied by 1.25 (arbitrarily selected; sensitivity study showed negligible effect of this assumption up to 20% differences).Datasets overview:categories.txt - represents dates split into three categories of lidar observations. The aim of categories is to separate particular days of lidar observations into bins with similar conditions in terms of: measurement length, cloudiness, pollination bell shape occurrence and presence of other aerosol events. Distinguished three categories, where category 1 is the least, and 3 the most restrictive (refer to section Datasets Specification below).vdr_raw.zip - volume depolarization ratio (VDR) dataset based on lidar quick-looks from category 3 in categories.txt. Separate file represents matrix of VDRs obtained from framing of a bell-like shape and removing the background from it during each day in category 3. Pixels of the bell, based on their pixel-color levels, were converted into VDR from the scale given for each quick-look.vdr_mean_with_dispersions.txt - represents mean and dispersion measurements based on the values retrieved in vdr_raw.zip, file consists of: mean, standard deviation, 25th percentile, 50th percentile, 75th percentile, 90th percentile.Datasets specification:1. categories.txt:file structure:header - file metadata (file content information, measurement location, label naming convention, categories description).dataset - lidar's quick-look dates classified into predefined categories and split into columns. If date was not classified into next category is marked as "None".column by index representation (index. label name - description):DATE_CATEGORY_1_532 - dates in which following conditions were fulfilled (for lidar quick-look at 532 nm polarized channel): recorded &gt; 20h lidar observations; observed low clouds (&lt; 2km) for less than 1h; observed clouds &lt; 4km for less than 2.5h of time.DATE_CATEGORY_2_532 - dates in which following conditions were fulfilled (for lidar quick-look at 532 nm polarized channel): number of days in category 1for which the bell-like shape in depolarization plots is present.DATE_CATEGORY_3_532 - dates in which following conditions were fulfilled (for lidar quick-look at 532 nm polarized channel): number of days in category 2 for which no aerosol layers discernible above boundary layer.2. vdr_raw.zip:general structure - each file represents one pollination event on which bell-like shape was identified (category 3 from categories.txt).files count: 54.files type: txt.filenames format: "YYYYMMDDLidarPol532nm.txt". Example: "20131024LidarPol532nm.txt".dataset type: float, None.file structure:header - file metadata (file content information, measurement location, source, value representation, axes information, date, lidar channel, bell coordinates in pixels on lidar quick look).dataset - bell-like shape with background removed as a matrix of image in terms of VDR.3. vdr_mean_with_dispersions.txt:identified cases: 54 (category 3 from categories.txt), based on vdr_raw.zip.file structure:header - file metadata (file content information, measurement location, label naming convention).dataset - split into columns pollination event date with measurements of: mean, standard deviation, 25th percentile, 50th percentile, 75th percentile, 90th percentile. If background was removed in particular place VDR in that place is marked as "None".column by index representation (index. label name - description):DATE - processed quick-look date in format: "YYYY-MM-DD".MEAN_532 - raw VDR average at polarized 532 nm channel.ST_DEV_532 - raw VDR standard deviation at polarized 532 nm channel.Q25_532 - raw VDR 25th percentile at polarized 532 nm channel.Q50_532 - raw VDR 50th percentile at polarized 532 nm channel.Q75_532 - raw VDR 75th percentile at polarized 532 nm channel.Q90_532 - raw VDR 90th percentile at polarized 532 nm channel.General information:Files encoding: Windows (lines: \r\n), UTF-8.Decimal separator: dot (.).Column separator: tab (\t).Header denoted as: hashtag (#).No data denoted as: (None).Date format represented by ISO 8601.ATTENTION:We offer a free access to this dataset. The user is however encouraged to share the information on the data use with the Remote Sensing Laboratory by sending an e-mail to rslab@fuw.edu.pl.In the case this dataset is used for a scientific communication (publication, conference contribution, thesis) we would kindly ask to acknowledge this data provision by adding the following statement in Acknowledgments: "We acknowledge the data originators A.Tomczak and I.S.Stachlewska for the quality-assurance, evaluation, and provision of data sets of the Remote Sensing Laboratory at the Faculty of Physics of the University of Warsaw, Poland."