CBP Water Quality Monitoring Subset (1984-2018), LE5 2

This product was developed as part of the project supported by the grant from and the National Oceanic and Atmospheric Administration’s Ocean Acidification Program under award NA18OAR0170430 to the Virginia Institute of Marine Science. The data product consists of water quality data for tidal 98 stations for 1984­­–2018. The source data used to generate this product were downloaded from the Chesapeake Bay Program’s (CBP) data hub. Out of the total of 255 monitoring stations in the Tidal Monitoring Program, we selected 98 with the long monitoring record (30 years or longer). The following variables were downloaded from the data hub at the native temporal and vertical resolution (between one and four cruises per month and approximately 10 depth levels sampled between 0 and 37 m) for 1984–2018: water temperature (T), salinity (S), pH, total alkalinity (TA), dissolved oxygen (DO) , and chlorophyll (Chl). All pH data prior to 1998 were removed because of the data quality concerns (Herrmann et al., 2020). Briefly, we found a dramatic difference in long-term trends between stations measured by institutions in the state of Virginia and stations measured by the state of Maryland, particularly from late spring to early fall. The boundary between the station groups runs east–west within the mesohaline portion of the bay, where the Potomac River estuary intersects the mainstem bay. The boundary separates strong negative linear trends to the south (Virginia stations) from neutral and weakly positive linear trends to the north (Maryland stations).
For all variables, data entries marked with CBP’s “Problem” and “Qualifier” flags were removed. Additionally, all variables were scanned for extreme outliers: for each variable, data from all stations, depths, and times were combined into a single composite sample for which the 75th and 25th percentiles (i.e., the upper and lower quantiles) and the interquartile range (the difference between the upper and lower quantiles) were calculated. Extreme outliers were defined as the values falling outside of a certain number (censoring criterion) of interquartile ranges from the upper and lower quantiles.
acknowledgement=CBP data hub (https://www.chesapeakebay.net/what/data) and NOAA OA Program funding: "RVA-OA2017: Vulnerability of the largest U.S. estuary to acidification: Implications of declining pH for shellfish hatcheries in the Chesapeake Bay
cdm_data_type=TimeSeriesProfile
cdm_profile_variables=time
cdm_timeseries_variables=station_id
contributor_email=[e-mail]
contributor_name=Marjy Friedrichs
contributor_role=principalInvestigator
contributor_role_vocabulary=https://vocab.nerc.ac.uk/collection/G04/current/
contributor_url=http://www.vims.edu/people/friedrichs_ma/
Conventions=CF-1.7, ACDD-1.3, IOOS-1.2
date_metadata_modified=2021-08-26T18:48:22Z
Easternmost_Easting=-76.59306
featureType=TimeSeriesProfile
geospatial_bounds=POINT(37.056 -76.59306)
geospatial_bounds_crs=EPSG:4326
geospatial_bounds_vertical_crs=EPSG:4297
geospatial_lat_max=37.056
geospatial_lat_min=37.056
geospatial_lat_units=degrees_north
geospatial_lon_max=-76.59306
geospatial_lon_min=-76.59306
geospatial_lon_units=degrees_east
geospatial_vertical_max=11.0
geospatial_vertical_min=1.0
geospatial_vertical_positive=down
geospatial_vertical_units=m
gts_ingest=False
history=[2021-08-26] Created NetCDF4 file from maracoos_set98.mat
id=LE5.2
infoUrl=https://www.chesapeakebay.net/what/downloads/cbp_water_quality_database_1984_present
institution=Penn State
keywords_vocabulary=GCMD Science Keywords
naming_authority=edu.psu.met
nodc_template_version=NODC_TimeSeriesProfile_Template_v2.0
Northernmost_Northing=37.056
platform=fixed
platform_id=cbp_LE5.2
platform_name=Chesapeake Bay Buoy - LE5.2
platform_vocabulary=https://mmisw.org/ont/ioos/platform
processing_level=For temperature, salinity, pH, alkalinity, oxygen, and chlorophyll: QA/QC of the open-source Chesapeake Bay Program water quality monitoring data (http://data.chesapeakebay.net/WaterQuality); model output for all other variables
project=NSF OCE‐1537013 OCE‐1536996; NOAA OAP: NA18OAR0170430; PI: Marjorie Friedrichs ([e-mail])
references=https://www.chesapeakebay.net/what/downloads/cbp_water_quality_database_1984_present
source=Data from maracoos_set98.mat file created by PSU/VIMS
sourceUrl=(local files)
Southernmost_Northing=37.056
standard_name_vocabulary=CF Standard Name Table v55
subsetVariables=station_id, depth
time_coverage_duration=PT85200S
time_coverage_end=2018-12-05T09:40:00Z
time_coverage_resolution=PT300S
time_coverage_start=1984-09-25T00:01:00Z
Westernmost_Easting=-76.59306

该产品系在国家海洋和大气管理局海洋酸化项目（NOAA OA Program）资助下，根据项目资助编号 NA18OAR0170430，由弗吉尼亚海洋科学研究所（Virginia Institute of Marine Science）承担的项目研发而成。数据产品包含1984年至2018年间潮汐98个监测站的水质数据。用于生成此产品的源数据来源于切萨皮克湾计划（Chesapeake Bay Program, CBP）的数据中心。在潮汐监测计划的255个监测站中，我们选择了具有长期监测记录（30年或更长时间）的98个站。以下变量在原始时间尺度和垂直分辨率（每月一到四次巡航，0至37米之间约10个深度层次）下从数据中心下载：水温（T）、盐度（S）、pH值、总碱度（TA）、溶解氧（DO）和叶绿素（Chl）。由于数据质量担忧（Herrmann et al., 2020），在1998年之前的所有pH数据已被移除。简而言之，我们发现弗吉尼亚州和马里兰州的机构测量的站点与马里兰州测量的站点之间在长期趋势上存在显著差异，尤其是在春末至夏初期间。站点组之间的分界线位于海湾的中盐度部分，即在波托马克河三角洲与主海湾交汇处的东西方向。分界线将南部（弗吉尼亚州站点）的强烈负线性趋势与北部（马里兰州站点）的中性和轻微正线性趋势分开。对于所有变量，所有站点、深度和时间的数据都被合并成一个单独的综合样本，以计算第75和第25百分位数（即上和下分位数）以及四分位距（上和下分位数之间的差异）。极端异常值被定义为超出一定数量的四分位距（ censoring criterion ）的上和下分位数之外。