CBP Water Quality Monitoring Subset (1984-2018), TF2 4

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=2021-08-26T18:48:42Z
Easternmost_Easting=-77.2654
featureType=TimeSeriesProfile
geospatial_bounds=POINT(38.5301 -77.2654)
geospatial_bounds_crs=EPSG:4326
geospatial_bounds_vertical_crs=EPSG:4297
geospatial_lat_max=38.5301
geospatial_lat_min=38.5301
geospatial_lat_units=degrees_north
geospatial_lon_max=-77.2654
geospatial_lon_min=-77.2654
geospatial_lon_units=degrees_east
geospatial_vertical_max=9.4
geospatial_vertical_min=0.3
geospatial_vertical_positive=down
geospatial_vertical_units=m
gts_ingest=False
history=[2021-08-26] Created NetCDF4 file from maracoos_set98.mat
id=TF2.4
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=38.5301
platform=fixed
platform_id=cbp_TF2.4
platform_name=Chesapeake Bay Buoy - TF2.4
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=38.5301
standard_name_vocabulary=CF Standard Name Table v55
subsetVariables=station_id, depth
time_coverage_duration=PT84719S
time_coverage_end=2018-12-10T11:24:00Z
time_coverage_resolution=PT85319S
time_coverage_start=1986-01-06T11:45:00Z
Westernmost_Easting=-77.2654

本产品系在国家海洋与大气管理局海洋酸化项目（NOAA OA Program）资助下，由弗吉尼亚海洋科学研究所（Virginia Institute of Marine Science）承建的项目所开发。该数据产品包含了1984至2018年间，针对潮汐98个监测站的水质数据。用于生成该产品的原始数据，系从切萨皮克湾项目（Chesapeake Bay Program，简称CBP）的数据中心下载。在潮汐监测计划的255个监测站中，我们选取了具有长期监测记录（30年或以上）的98个站进行数据收集。从数据中心下载的数据，保持了其原始时间和垂直分辨率（每月一次至四次巡航，深度介于0至37米之间，采样大约10个深度层级），包括水温（T）、盐度（S）、pH值、总碱度（TA）、溶解氧（DO）和叶绿素（Chl）。由于数据质量的问题（Herrmann等人，2020年），所有1998年之前的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机构测量的站点之间，长期趋势存在显著差异，特别是在晚春至初秋期间。站点组之间的分界线位于海湾的中咸水区域，即波托马克河河口与主湾交汇处的东西方向。该分界线将向南的强烈负线性趋势（弗吉尼亚州站点）与向北的中性及弱正线性趋势（马里兰州站点）分开。对于所有变量，已移除标记为CBP的“问题”和“限定符”标志的数据条目。此外，对所有变量进行了极端异常值检测：对于每个变量，将所有站点、深度和时间的观测数据合并成一个单一的综合样本，计算其第75和第25百分位数（即上四分位数和下四分位数）以及四分位距（上四分位数与下四分位数之差）。定义极端异常值为位于上四分位数和下四分位数之外一定数量（屏蔽标准）的四分位距之外的数据值。