# header_lines : 147
#
# ------------------------------------------------------------->>>>
# DATA SET NAME
#
# dataset_name: ch4_spf_surface-pfp_1_ccgg_event
#
# ------------------------------------------------------------->>>>
# DESCRIPTION
#
# dataset_description: Atmospheric Methane Dry Air Mole Fractions from NOAA GML Tall Tower and other Continental Sites  2005-Present
#
# ------------------------------------------------------------->>>>
# CITATION
#
# dataset_citation: Andrews, A., Crotwell, A., Crotwell, M., Handley, P., Higgs, J., Kofler, J., Lan, X., Legard, T., Madronich, M., McKain, K., Miller, J., Moglia, E., Mund, J., Neff, D., Newberger, T., Petron, G., Turnbull, J., Vimont, I., Wolter, S., & NOAA Global Monitoring Laboratory. (2023). NOAA Global Greenhouse Gas Reference Network Flask-Air PFP Sample Measurements of CH4 at Tall Tower and other Continental Sites, 2005-Present [Data set]. NOAA GML. https://doi.org/10.15138/35JE-6D55 Version: 2023-08-23.
#
# ------------------------------------------------------------->>>>
# FAIR USE POLICY
#
# dataset_fair_use: These data are made freely available to the public and the scientific community in the belief that their wide dissemination will lead to greater understanding and new scientific insights. To ensure that GML receives fair credit for their work please include relevant citation text in publications. We encourage users to contact the data providers, who can provide detailed information about the measurements and scientific insight.  In cases where the data are central to a publication, coauthorship for data providers may be appropriate. 
#
# ------------------------------------------------------------->>>>
# WARNING
#
# dataset_warning: Every effort is made to produce the most accurate and precise measurements possible.  However, we reserve the right to make corrections to the data based on recalibration of standard gases or for other reasons deemed scientifically justified.  We are not responsible for results and conclusions based on use of these data without regard to this warning.
#
# ------------------------------------------------------------->>>>
# GLOBAL ATTRIBUTES
#
# site_code : SPF
# site_name : Antarctic Firn Air
# site_country : United States
# site_country_flag : https://gml.noaa.gov/webdata/ccgg/ObsPack/images/flags/UNST0001.GIF
# site_latitude : -73.8658
# site_longitude : 163.687
# site_elevation : 1623.0
# site_elevation_unit : masl
# site_position_comment : This is the nominal location of the site. The sampling location at many sites has changed over time, and we report here the most recent nominal location. The actual sampling location for each observation is not necessarily the site location. The sampling locations for each observation are reported in the latitude, longitude, and altitude variables.
# site_utc2lst : 12.0
# site_utc2lst_comment : Add 'site_utc2lst' hours to convert a time stamp in UTC (Coordinated Universal Time) to LST (Local Standard Time).
# dataset_creation_date : 2023-08-23T12:43:40.384141
# dataset_num : 53
# dataset_name : ch4_spf_surface-pfp_1_ccgg_event
# dataset_parameter : ch4
# dataset_parameter_name : Methane
# dataset_parameter_industrial_name : Methane
# dataset_project : surface-pfp
# dataset_platform : fixed
# dataset_selection : event
# dataset_selection_tag : event
# dataset_comment : Firn air sampling in Antarctica; i.e. not ambient air.
# dataset_calibration_scale : CH4_X2004A
# dataset_start_date : 2013-12-04T09:10:00Z
# dataset_stop_date : 2014-01-09T08:58:44Z
# dataset_usage_description : Please cite the product's citation when using data from this dataset.
# dataset_provider_license : These data were produced by NOAA and are not subject to copyright protection in the United States. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0-1.0).
# dataset_reference_total_listed : 0
# dataset_contribution : These data are provided by NOAA. Principal investigators include Xin Lan (NOAA).
# lab_total_listed : 1
# lab_1_number : 1
# lab_1_abbr : NOAA
# lab_1_name : NOAA Global Monitoring Laboratory
# lab_1_address1 : 325 Broadway
# lab_1_address2 : NOAA R/GML-1
# lab_1_address3 : Boulder, CO 80305-3328
# lab_1_country : United States
# lab_1_url : https://gml.noaa.gov/ccgg/
# lab_1_parameter : Lab has contributed measurements for: ch4
# lab_1_country_flag : https://gml.noaa.gov/webdata/ccgg/ObsPack/images/flags/UNST0001.GIF
# lab_1_logo : https://gml.noaa.gov/webdata/ccgg/ObsPack/images/logos/noaa_medium.png
# lab_1_ongoing_atmospheric_air_comparison : T
# provider_total_listed : 1
# provider_1_name : Xin Lan
# provider_1_address1 : NOAA GML
# provider_1_address2 : 325 Broadway R/GML-1
# provider_1_address3 : Boulder, CO 80305-3328
# provider_1_country : United States
# provider_1_affiliation : National Oceanic and Atmospheric Administration
# provider_1_email : Xin.Lan@noaa.gov
# provider_1_parameter : Provider has contributed measurements for: ch4
# ------------------------------------------------------------->>>>
# VARIABLE ATTRIBUTES
#
# site_code:long_name : site_name_abbreviation.
# site_code:comment : Site code is an abbreviation for the sampling site name.
# time_components:_FillValue : -9
# time_components:long_name : integer_components_of_UTC_date/time
# time_components:order : year, month, day, hour, minute, second
# time_components:comment : Calendar time components as integers. Times and dates are UTC. Time-averaged values are reported at the start of the averaging interval.
# datetime:long_name : air_sample_date_and_time_in_UTC
# datetime:comment : Air sample date and time in UTC ISO 8601 format. Time-averaged values are reported at the start of the averaging interval.
# time_decimal:_FillValue : -999.999
# time_decimal:long_name : sample_decimal_year_in_UTC
# time_decimal:comment : decimal year in UTC. Time-averaged values are reported at the start of the averaging interval.
# air_sample_container_id:long_name : Air_Sample_Container_ID
# air_sample_container_id:comment : ID of air sample container. See provider_comment if available.
# value:_FillValue : -999.999
# value:long_name : measured_mole_fraction_of_trace_gas_in_dry_air
# value:units : nanomol mol-1
# value:comment : Mole fraction reported in units of nanomol mol-1 (10-9 mol per mol of dry air); abbreviated as ppb (parts per billion).
# value:scale_comment : CH4_X2004A
# value_unc:_FillValue : -999.999
# value_unc:long_name : estimated_uncertainty_in_reported_value
# value_unc:units : nanomol mol-1
# value_unc:comment : This is the estimated uncertainty of the reported value. See provider_comment if available.
# latitude:_FillValue : -999.999
# latitude:standard_name : latitude
# latitude:long_name : sample_latitude_in_decimal_degrees
# latitude:units : degrees_north
# latitude:comment : Latitude at which air sample was collected.
# longitude:_FillValue : -999.999
# longitude:standard_name : longitude
# longitude:long_name : sample_longitude_in_decimal_degrees
# longitude:units : degrees_east
# longitude:comment : Longitude at which air sample was collected using a range of -180 degrees to +180 degrees.
# altitude:_FillValue : -999.999
# altitude:standard_name : altitude
# altitude:long_name : sample_altitude_in_meters_above_sea_level
# altitude:units : m
# altitude:comment : Altitude (in meters above sea level). See provider_comment if available.
# altitude:provider_comment : Altitude for this dataset is the sum of surface elevation (masl) and sample intake height (magl).
# elevation:_FillValue : -999.999
# elevation:standard_name : elevation
# elevation:long_name : surface_elevation_in_meters_above_sea_level
# elevation:units : m
# elevation:comment : Surface elevation in meters above sea level. See provider_comment if available.
# intake_height:_FillValue : -999.999
# intake_height:long_name : sample_intake_height_in_meters_above_ground_level
# intake_height:units : m
# intake_height:comment : Sample intake height in meters above ground level (magl). See provider_comment if available.
# method:long_name : air_sample_collection_method
# method:comment : Air sample collection method. See provider_comment if available.
# method:provider_comment : A single-character code is used to identify the sample collection method. The codes are: A - The automated or manual filling of a whole air sample using the Programmable Flask Package (PFP) and Programmable Compressor Package (PCP)air sampling devices. The air sample is contained in a 0.7 liter borosilicate glass container (flask) fitted with two Glass Expansion high vacuum glass piston valves sealed with PTFE O-rings. The flasks are typically flushed with 10 liters (aircraft samples) or 75 liters (tower samples) of ambient air and then pressurized to 40 psia. Air is delivered through an intake tube using two diaphragm pumps connected in series and controlled with a microprocessor. The flow rate is approximately 15 L/min at sea level. See Sweeney et al. 2015 and Andrews et al. 2014 for more details. C - Air samples are collected as with method 'A', but the sample air is dried before sample collection. Flasks are not pre-filled with ambient air before flushing and collecting the air sample. I - Air is sampled from a 15L spherical stainless steel mixing volume after being filled with ambient air that was pulled through an M&C Techgroup Model ECP 20-2 gas chiller using an integrating compressor and mass flow controller. The two stainless steel dryer traps are plumbed in series, held at approximately 5 degrees C and the condensed water is removed with a peristaltic pump. Prior to sample collection, an additional glass conditioning step known as "prefilling" occurs where the glass containers are flushed and filled with ambient air and then vented and flushed immediately before air sample collection. This is a glass conditioning step that addresses glass wall effects of the gases of interest. After 'prefilling', the integration starts with a high flow rate of 3.8 SLM and decreases over time to 0.29 SLM over 1 hour. The resulting one hour time averaged ambient air sample is compressed into a 0.75 liter borosilicate glass container (flask) fitted with 2 Glass Expansion high vacuum glass valves and PTFE O-rings. The flask is typically filled to 40 psia. (See Turnbull, J.C., Guenther, D., Karion, A., Sweeney, C., Anderson, E., Andrews, A.E., Kofler, J., Miles, N.L., Newberger, T., Richardson, S.J., Tans, P.P., 2012. An integrated flask sample collection system for greenhouse gas measurements. Atmos. Meas. Tech. 5, 2321-2327.) B - Air samples are collected as with method 'R', but with an additional drying step using one of several techniques. In one method, e.g. site=ACT, air samples were dried with a two-stage chiller cooled to 5 degrees C; those taken below 3000 m MSL were also pressurized to 40 psia to further facilitate air sample drying (Baier et al. 2019). At tower sampling sites, M&C chillers with temperatures set to approximately 3 degrees C and sub-ambient pressure due to high flow are used (Andrew et al. 2014). At CRV tower, a two-stage chiller set to -26 degrees C is used. R - Air samples are collected as with method 'A', but with an additional glass conditioning step known as "prefilling". During prefilling, the glass containers are flushed and filled with ambient air and then vented and flushed immediately before air sample collection. This is a glass conditioning step that addresses glass wall effects of the gasses of interest (Andrews et al. 2014). X - Testing method for pfp drying experiments. CP-> chiller pressurized
# event_number:long_name : Unique_Air_Sample_Event_Number
# event_number:comment : Identifies each discrete air sample collected at some time and location with a unique sample event number.  The event number (reported as a string) can be used to relate measurements of different trace gases and isotopes from the same sample.
# instrument:long_name : instrument_ID_to_detect_atmospheric_parameter
# instrument:comment : Instrument ID used to detect atmospheric parameter. See provider_comment if available.
# analysis_datetime:long_name : air_sample_measurement_date_and_time_in_LT
# analysis_datetime:comment : Air sample measurement date and time in LT. See provider_comment if available.
# qcflag:long_name : quality_control_flag
# qcflag:comment : This quality control flag is provided by the contributing PIs. See provider_comment if available.
# qcflag:provider_comment : This is the NOAA 3-character quality control flag.  Column 1 is the REJECTION flag. An alphanumeric other than a period (.) in the FIRST column indicates a sample with obvious problems during collection or analysis. This measurement should not be interpreted. Column 2 is the SELECTION flag. An alphanumeric other than a period (.) in the SECOND column indicates a sample that is likely valid but does not meet selection criteria determined by the goals of a particular investigation. For example, it might not have been obtained during 'background' conditions.  Column 3 is the INFORMATION flag. An alphanumeric other than a period (.) in the THIRD column provides additional information about the collection or analysis of the sample. A P in the 3rd column of the QC flag indicates the measurement result is preliminary and has not yet been carefully examined by the PI.  The P flag is removed once the quality of the measurement has been determined.
#
# VARIABLE ORDER
#
site_code year month day hour minute second datetime time_decimal air_sample_container_id value value_unc latitude longitude altitude elevation intake_height method event_number instrument analysis_datetime qcflag
SPF 2013 12 4 9 10 0 2013-12-04T09:10:00Z 2013.9243340943683 3928-01 1771.95 0.91 -75.1017 123.395 0.45 3233.0 -3232.55 A 362420 H11 2014-01-08T04:58:00 ...
SPF 2013 12 4 9 11 0 2013-12-04T09:11:00Z 2013.924335996956 3928-02 1769.94 0.91 -75.1017 123.395 0.1 3233.0 -3232.9 A 362421 H11 2014-01-08T05:14:00 ...
SPF 2013 12 4 9 21 0 2013-12-04T09:21:00Z 2013.9243550228312 3928-03 1766.57 0.91 -75.1017 123.395 -0.1 3233.0 -3233.1 A 362422 H11 2014-01-08T05:30:00 ...
SPF 2013 12 4 9 31 0 2013-12-04T09:31:00Z 2013.9243740487063 3928-04 1768.48 0.91 -75.1017 123.395 -0.3 3233.0 -3233.3 A 362423 H11 2014-01-08T05:47:00 ...
SPF 2013 12 4 9 41 0 2013-12-04T09:41:00Z 2013.9243930745815 3928-05 1767.23 0.91 -75.1017 123.395 -0.5 3233.0 -3233.5 A 362424 H11 2014-01-08T06:03:00 ...
SPF 2013 12 4 9 51 0 2013-12-04T09:51:00Z 2013.9244121004567 3928-06 2042.18 0.91 -75.1017 123.395 -0.7 3233.0 -3233.7 A 362425 H11 2014-01-08T06:19:00 C..
SPF 2013 12 5 6 8 50 2013-12-05T06:08:50Z 2013.926729134957 3928-07 1767.48 0.91 -75.1017 123.395 0.45 3233.0 -3232.55 A 362426 H11 2014-01-08T06:35:00 ...
SPF 2013 12 5 6 18 50 2013-12-05T06:18:50Z 2013.9267481608322 3928-08 1767.38 0.91 -75.1017 123.395 0.1 3233.0 -3232.9 A 362427 H11 2014-01-08T06:51:00 ...
SPF 2013 12 5 6 28 51 2013-12-05T06:28:51Z 2013.9267672184171 3928-09 1767.48 0.91 -75.1017 123.395 -0.1 3233.0 -3233.1 A 362428 H11 2014-01-08T07:07:00 ...
SPF 2013 12 5 6 38 54 2013-12-05T06:38:54Z 2013.9267863394216 3928-10 1767.43 0.91 -75.1017 123.395 -0.3 3233.0 -3233.3 A 362429 H11 2014-01-08T07:23:00 ...
SPF 2013 12 5 6 48 52 2013-12-05T06:48:52Z 2013.9268053018773 3928-11 1765.25 0.91 -75.1017 123.395 -0.5 3233.0 -3233.5 A 362430 H11 2014-01-08T07:39:00 ...
SPF 2013 12 5 6 58 53 2013-12-05T06:58:53Z 2013.9268243594622 3928-12 1766.96 0.91 -75.1017 123.395 -0.7 3233.0 -3233.7 A 362431 H11 2014-01-08T07:55:00 ...
SPF 2013 12 8 7 9 0 2013-12-08T07:09:00Z 2013.935062785388 3923-01 1766.4 0.91 -75.1017 123.395 0.45 3233.0 -3232.55 A 362408 H11 2014-01-08T01:46:00 ...
SPF 2013 12 8 7 19 0 2013-12-08T07:19:00Z 2013.9350818112632 3923-02 1767.08 0.91 -75.1017 123.395 0.1 3233.0 -3232.9 A 362409 H11 2014-01-08T02:02:00 ...
SPF 2013 12 8 7 29 0 2013-12-08T07:29:00Z 2013.9351008371384 3923-03 1766.94 0.91 -75.1017 123.395 -0.1 3233.0 -3233.1 A 362410 H11 2014-01-08T02:18:00 ...
SPF 2013 12 8 7 39 0 2013-12-08T07:39:00Z 2013.9351198630136 3923-04 1767.51 0.91 -75.1017 123.395 -0.3 3233.0 -3233.3 A 362411 H11 2014-01-08T02:34:00 ...
SPF 2013 12 8 7 49 0 2013-12-08T07:49:00Z 2013.9351388888888 3923-05 1765.81 0.91 -75.1017 123.395 -0.5 3233.0 -3233.5 A 362412 H11 2014-01-08T02:50:00 ...
SPF 2013 12 8 7 59 0 2013-12-08T07:59:00Z 2013.935157914764 3923-06 1768.72 0.91 -75.1017 123.395 0.0 3233.0 -3233.0 A 362413 H11 2014-01-08T03:06:00 ...
SPF 2013 12 8 10 8 59 2013-12-08T10:08:59Z 2013.9354052194317 3923-07 1764.58 0.91 -75.1017 123.395 0.45 3233.0 -3232.55 A 362414 H11 2014-01-08T03:22:00 ...
SPF 2013 12 8 10 18 54 2013-12-08T10:18:54Z 2013.935424086758 3923-08 1768.47 0.91 -75.1017 123.395 0.1 3233.0 -3232.9 A 362415 H11 2014-01-08T03:38:00 ...
SPF 2013 12 8 10 28 51 2013-12-08T10:28:51Z 2013.9354430175038 3923-09 1764.53 0.91 -75.1017 123.395 -0.1 3233.0 -3233.1 A 362416 H11 2014-01-08T03:54:00 ...
SPF 2013 12 8 10 38 53 2013-12-08T10:38:53Z 2013.9354621067985 3923-10 1764.96 0.91 -75.1017 123.395 -0.3 3233.0 -3233.3 A 362417 H11 2014-01-08T04:10:00 ...
SPF 2013 12 8 10 48 48 2013-12-08T10:48:48Z 2013.9354809741249 3923-11 1765.33 0.91 -75.1017 123.395 -0.5 3233.0 -3233.5 A 362418 H11 2014-01-08T04:26:00 ...
SPF 2013 12 8 10 58 52 2013-12-08T10:58:52Z 2013.935500126839 3923-12 1763.24 0.91 -75.1017 123.395 -0.7 3233.0 -3233.7 A 362419 H11 2014-01-08T04:42:00 ...
SPF 2013 12 18 7 18 48 2013-12-18T07:18:48Z 2013.96247869102 3916-02 1764.96 1.31 -75.1017 123.395 0.1 3233.0 -3232.9 A 364282 H6 2014-02-14T00:56:00 ...
SPF 2013 12 18 7 28 51 2013-12-18T07:28:51Z 2013.9624978120244 3916-03 1764.28 1.31 -75.1017 123.395 -0.1 3233.0 -3233.1 A 364283 H6 2014-02-14T01:13:00 ...
SPF 2013 12 18 7 38 55 2013-12-18T07:38:55Z 2013.9625169647388 3916-04 1760.38 1.31 -75.1017 123.395 -0.3 3233.0 -3233.3 A 364284 H6 2014-02-14T01:29:00 ...
SPF 2013 12 18 7 48 55 2013-12-18T07:48:55Z 2013.962535990614 3916-05 1762.3 1.31 -75.1017 123.395 -0.5 3233.0 -3233.5 A 364285 H6 2014-02-14T01:45:00 ...
SPF 2013 12 18 7 58 55 2013-12-18T07:58:55Z 2013.9625550164892 3916-06 -999.99 -999.999 -75.1017 123.395 -0.7 3233.0 -3233.7 A 364286 H6 2014-02-14T02:01:00 B..
SPF 2013 12 18 8 8 41 2013-12-18T08:08:41Z 2013.9625735984273 3916-07 1755.48 1.31 -75.1017 123.395 -1.2 3233.0 -3234.2 A 364287 H6 2014-02-14T02:18:00 ...
SPF 2013 12 18 8 18 50 2013-12-18T08:18:50Z 2013.9625929096906 3916-08 1763.28 1.31 -75.1017 123.395 0.1 3233.0 -3232.9 A 364288 H6 2014-02-14T02:34:00 ...
SPF 2013 12 18 8 28 50 2013-12-18T08:28:50Z 2013.9626119355657 3916-09 1761.89 1.31 -75.1017 123.395 -0.1 3233.0 -3233.1 A 364289 H6 2014-02-14T02:50:00 ...
SPF 2013 12 18 8 38 52 2013-12-18T08:38:52Z 2013.9626310248605 3916-10 1760.78 1.31 -75.1017 123.395 -0.3 3233.0 -3233.3 A 364290 H6 2014-02-14T03:06:00 ...
SPF 2013 12 18 8 48 54 2013-12-18T08:48:54Z 2013.9626501141552 3916-11 1762.11 1.31 -75.1017 123.395 -0.5 3233.0 -3233.5 A 364291 H6 2014-02-14T03:22:00 ...
SPF 2013 12 18 8 58 51 2013-12-18T08:58:51Z 2013.962669044901 3916-12 1761.48 1.31 -75.1017 123.395 -0.7 3233.0 -3233.7 A 364292 H6 2014-02-14T03:39:00 ...
SPF 2013 12 18 15 8 51 2013-12-18T15:08:51Z 2013.963373002283 3916-01 1766.73 1.31 -75.1017 123.395 0.45 3233.0 -3232.55 A 364281 H6 2014-02-14T00:40:00 ...
SPF 2014 1 9 7 8 46 2014-01-09T07:08:46Z 2014.0227335743277 0000-01 1757.35 0.91 -75.1017 123.395 0.45 3233.0 -3232.55 A 364293 H11 2014-02-18T15:32:00 ...
SPF 2014 1 9 7 28 47 2014-01-09T07:28:47Z 2014.0227716577879 0000-03 1757.99 0.91 -75.1017 123.395 -0.1 3233.0 -3233.1 A 364294 H11 2014-02-18T15:48:00 ...
SPF 2014 1 9 7 38 47 2014-01-09T07:38:47Z 2014.022790683663 0000-04 1755.19 0.91 -75.1017 123.395 -0.3 3233.0 -3233.3 A 364295 H11 2014-02-18T16:04:00 ...
SPF 2014 1 9 7 48 46 2014-01-09T07:48:46Z 2014.0228096778285 0000-05 1757.59 0.91 -75.1017 123.395 -0.5 3233.0 -3233.5 A 364296 H11 2014-02-18T16:20:00 ...
SPF 2014 1 9 7 58 46 2014-01-09T07:58:46Z 2014.0228287037037 0000-06 1756.76 0.91 -75.1017 123.395 -0.7 3233.0 -3233.7 A 364297 H11 2014-02-18T16:36:00 ...
SPF 2014 1 9 8 8 49 2014-01-09T08:08:49Z 2014.0228478247084 0000-07 1755.06 0.91 -75.1017 123.395 0.45 3233.0 -3232.55 A 364298 H11 2014-02-18T16:52:00 ...
SPF 2014 1 9 8 28 51 2014-01-09T08:28:51Z 2014.0228859398783 0000-09 1757.8 0.91 -75.1017 123.395 -0.1 3233.0 -3233.1 A 364299 H11 2014-02-18T17:08:00 ...
SPF 2014 1 9 8 38 47 2014-01-09T08:38:47Z 2014.0229048389142 0000-10 1752.92 0.91 -75.1017 123.395 -0.3 3233.0 -3233.3 A 364300 H11 2014-02-18T17:24:00 ...
SPF 2014 1 9 8 48 45 2014-01-09T08:48:45Z 2014.0229238013699 0000-11 1757.46 0.91 -75.1017 123.395 -0.5 3233.0 -3233.5 A 364301 H11 2014-02-18T17:40:00 ...
SPF 2014 1 9 8 58 44 2014-01-09T08:58:44Z 2014.0229427955353 0000-12 1754.84 0.91 -75.1017 123.395 -0.7 3233.0 -3233.7 A 364302 H11 2014-02-18T17:57:00 ...