A 20-year (1998-2017) global sea surface dimethyl sulfide gridded dataset with daily resolution

This dataset contains (1) the matched and binned data used for constructing an artificial neural network (ANN) ensemble model to simulate the sea surface concentration of dimethyl sulfide (DMS); (2) the simulated global daily sea surface concentrations of DMS ranging from 1998 to 2017 by ANN model and the calculated total transfer velocities (Kt) and sea-to-air fluxes. The input variables of this ANN ensemble model include chlorophyll a, sea surface temperature (SST), mixed layer depth (MLD), nitrate, phosphate, silicate, dissolved oxygen (DO), downward short-wave radiation (DSWF), and sea surface salinity (SSS). The spatial resolution of the simulated dataset is 1°×1°. The units of DMS concentration, Kt, and flux are nmol L–1, m d–1, and μmol S m–2 d–1, respectively. Update Note In Version 4.0 and earlier versions, the sea ice cover data (from the OISST dataset) used to calculate Kt and DMS flux contained certain time periods with completely missing values, which were incorrectly replaced with zeros. This led to a significant overestimation of Kt and DMS flux in polar regions where sea ice coverage exists. The missing data periods include: November 27–28, 2011; January 7–9, 2016; April 18 to June 30, 2016; and January 7 to February 28, 2017. This issue was resolved beginning with Version 5.0 through the use of updated sea ice data. Compared to Version 5.0, the current version introduces a correction to a bug in the DMS concentration simulation. When input data were missing—primarily in polar regions—the DMS concentration should have been flagged as missing. However, it was previously assigned a value of 1.6031 nM in Version 5.0. In the current version, these values are now replaced with -999 to indicate missing data.本数据集包含两部分内容：(1) 用于构建人工神经网络（Artificial Neural Network, ANN）集合模型以模拟二甲基硫（dimethyl sulfide, DMS）海表浓度的匹配后分箱数据；(2) 1998年至2017年期间由该ANN集合模型模拟得到的全球逐日DMS海表浓度，以及计算得到的总转移速率（Kt）和海-气通量。 该ANN集合模型的输入变量包括叶绿素a、海表温度（Sea Surface Temperature, SST）、混合层深度（Mixed Layer Depth, MLD）、硝酸盐、磷酸盐、硅酸盐、溶解氧（Dissolved Oxygen, DO）、向下短波辐射（Downward Short-wave Radiation, DSWF）以及海表盐度（Sea Surface Salinity, SSS）。 模拟数据集的空间分辨率为1°×1°。DMS浓度、Kt和通量的单位分别为nmol L–1、m d–1和μmol S m–2 d–1。 ### 更新说明 在V4.0及更早版本中，用于计算Kt和DMS通量的海冰覆盖数据（源自OISST数据集）存在部分时段完全缺值的情况，且被错误地替换为0，这导致存在海冰覆盖的极地区域的Kt和DMS通量被显著高估。缺值时段包括：2011年11月27日至28日、2016年1月7日至9日、2016年4月18日至6月30日，以及2017年1月7日至2月28日。自V5.0起，通过使用更新后的海冰数据解决了该问题。 相较于V5.0，当前版本修复了DMS浓度模拟中的一处漏洞：当输入数据缺值（主要集中在极地地区）时，本应将DMS浓度标记为缺值，但在V5.0中其被错误赋值为1.6031 nM。在当前版本中，此类数值已被替换为-999以标识缺测数据。