Black Sea - Danube Delta - DIVAnd 4D seasonal analysis of Water body dissolved oxygen concentration 1970/2019 v2023

Water body dissolved oxygen concentration - Seasonal Climatology for NW Black Sea (region in front of Danube Delta months) for the period 1970-2019 on the domain: Lon E28.5-30.5°E, Lat N43.7-45.6°N. Season definition: winter: December-February, - spring: March-May, - summer: June-August, - autumn: September-November. Units: umol/l. Data Sources: observational data from SeaDataNet/EMODNet Chemistry Data Network. Description of DIVA analysis: The computation was done with the DIVAnd (Data-Interpolating Variational Analysis in n dimensions), version 2.7.9, using GEBCO 30sec topography for the spatial connectivity of water masses. Horizontal correlation length of 47.73km and vertical correlation length of 45m were applied. The horizontal resolution of the produced DIVAnd maps grids is 0.01 degrees. The vertical resolution is 17 depth levels: 0.0, 2.0, 4.0, 6.0, 8.0, 10.0, 15.0, 20.0, 25.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0, 100.0m. The error variance (epsilon2): 1 An anamorphosis transformation was applied to the data: threshold value=200. The mean value was used as background analysis field. Quality control of the observations was applied using the interpolated field: QCMETHOD=3 and visual inspection (Observations with residuals outside the minimum and maximum values of the 99% quantile were discarded from the analysis after thoroughly visual inspection).

黑海西北部（多瑙河三角洲前方海域）水体溶解氧浓度季节气候学数据集，时间范围为1970-2019年，研究区域为：东经28.5°~30.5°，北纬43.7°~45.6°。
季节划分标准如下：冬季为12月至次年2月，春季为3月至5月，夏季为6月至8月，秋季为9月至11月。
单位：微摩尔每升（μmol/L）。
数据来源：SeaDataNet/EMODNet化学数据网络的观测资料。
DIVAnd分析（n维数据插值变分分析，Data-Interpolating Variational Analysis in n dimensions）说明：本次计算采用版本为2.7.9的DIVAnd工具，空间水团连通性参考GEBCO 30秒分辨率地形数据；设置水平相关长度为47.73千米，垂直相关长度为45米。生成的DIVAnd分析格网水平分辨率为0.01度，垂直方向共设17个深度层：0.0、2.0、4.0、6.0、8.0、10.0、15.0、20.0、25.0、30.0、40.0、50.0、60.0、70.0、80.0、90.0、100.0米。误差方差（epsilon2）：1。对数据集实施了变形变换（anamorphosis transformation），阈值设定为200；以数据集均值作为背景分析场。基于插值场开展观测资料质量控制：采用QCMETHOD=3方法并辅以人工目视检查——经详细目视校验后，残差超出99%分位数极值范围的观测数据将被剔除出分析流程。