Raw underway Thermosalinograph (TSG) observations from the Southern Ocean Seasonal Experiment 2022 on the SA Agulhas II Voyage 053, July 2022

Here we present the 6-second resolution raw Thermosalinograph (TSG) data collected between 12 July and 30 July 2022 on the SA Agulhas II Voyage 053. A SeaBird SBE45 TSG is used to opportunistically collect underway near-surface temperature and conductivity measurements during research and monitoring cruises. Water is continuously pumped to the TSG from an intake located in the hull of the vessel, and the observations are continuously interfaced with navigational information. A temperature sensor close to the intake provides temperature measurements of the incoming water (T1). The temperature of the water inside the conductivity cell (T2) is used to accurately compute salinity (S) from the conductivity measurements (C). This cruise was included as a final component of the SCALE programme (Southern oCean seAsonaL Experiment, https://scale.org.za), a bottom-up endeavour of the SA scientific community to address the limited multidisciplinary knowledge on the seasonal cycle of the Southern Ocean. The seasonal cycle is an important mode of variability that couples the physical mechanisms of climate forcing to ecosystem response in phytoplankton diversity, primary production, and carbon export. Model simulations of the Southern Hemisphere tend to misestimate the magnitude and miss the timing of the Southern Ocean seasonal cycle both in terms of the seasonality of surface ocean warming and cooling, sea ice advancement/retreat, carbon dioxide exchanges and simulated primary production. Our capability to predict the ongoing shifts and future responses is therefore limited. This drives the need for more physical and biogeochemical data sets that address the problem of knowledge and model biases; firstly, to identify them, and secondly to characterise the associated mechanisms that will allow improved projections.

本报告呈现了于2022年7月12日至7月30日在SA Agulhas II航次053中采集的6秒分辨率原始热盐计（Thermosalinograph，TSG）数据。在研究及监测航次中，利用SeaBird SBE45 TSG设备偶然收集近表层温度及电导率测量数据。水体持续由船体内的取水口泵送至TSG，观测数据与导航信息实时对接。靠近取水口的温度传感器提供了进入水体的温度测量值（T1）。导电池内水体的温度（T2）被用于从电导率测量值（C）中精确计算盐度（S）。本次航次是SCALE项目（南方海洋季节性实验，https://scale.org.za）的最终组成部分，该项目是南非科学界自下而上的努力，旨在解决关于南大洋季节性循环的跨学科知识不足问题。季节性循环是气候强迫与浮游植物多样性、初级生产力和碳输出生态系统响应相互耦合的重要变化模式。对南半球的模型模拟往往高估或低估南大洋季节性循环的幅度及时间，包括表层海洋升温降温的季节性、海冰的推进/退缩、二氧化碳交换以及模拟的初级生产力。因此，我们预测当前变化和未来响应的能力受到限制。这促使我们迫切需要更多物理和生物地球化学数据集来解决知识与模型偏差问题；首先，以识别它们，其次，以描述相关的机制，这将有助于改善预测。