Lijing Cheng

Institute of Atmospheric Physics · International Center for Climate and Environment Sciences

AbstractSystematic biases in historical expendable bathythermograph (XBT) data are examined using two datasets: 4151 XBT?CTD side-by-side pairs from 1967 to 2011 and 218 653 global-scale XBT?CTD pairs (within one month and 1°) extracted from the World Ocean Database 2009 (WOD09) from 1966 to 2010. Using the side-by-side dataset, it was found that b...

eXpendable BathyThermograph (XBT) data were the major component of the ocean temperature profile observations from the late 1960s through early 2000s, and XBTs still continue to provide critical data to monitor surface and subsurface currents, meridional heat transport, and ocean heat content. Systematic errors have been identified in the XBT data,...

Earth’s energy imbalance (EEI) drives the ongoing global warming and can best be assessed across the historical record (that is, since 1960) from ocean heat content (OHC) changes. An accurate assessment of OHC is a challenge, mainly because of insufficient and irregular data coverage. We provide updated OHC estimates with the goal of minimizing ass...

http://159.226.119.60/cheng/ IAP ocean subsurface temperature dataset: 1940-2016 monthly, 1by1 degree, 41 vertical levels for 0-2000m.

Observational records of ocean heat content show that ocean warming is accelerating

A gridded salinity dataset with high resolution is essential for investigating global ocean salinity variability and understanding its role in climate and the ocean ecosystem. In this study, a new version of the Institute of Atmospheric Physics gridded salinity dataset with a higher resolution (0.5° by 0.5°) is provided by using a revised ensemble...

The heat content in the Indian Ocean has been increasing owing to anthropogenic greenhouse warming. Yet, where and how the anthropogenic heat is stored in the Indian Ocean have not been comprehended. Analysis of various observational and model-based datasets since the 1950s reveals a robust spatial pattern of the 0-700 m ocean heat content trend (Δ...

The near ubiquitous presence of numerical simulation has made case‐specific calculations of body temperatures following death possible so that accurate calculations of body temperatures can provide valuable information for estimating the time of death and can aid in forensic investigations. Here, a computational approach is described that has been...

Changes in ocean heat content (OHC), salinity, and stratification provide critical indicators for changes in Earth's energy and water cycles. These cycles have been profoundly altered due to the emission of greenhouse gasses and other anthropogenic substances by human activities, driving pervasive changes in Earth's climate system. In 2022, the wor...

The second version of the Chinese Academy of Sciences Earth System Model, CAS-ESM2-0, is a newcomer that contributes to Coupled Model Intercomparison Project simulations in the community. We evaluated the model’s performance in simulating the salinity for climatology, seasonal cycles, long-term trends, and time series of climatic metrics by compari...

The surface ocean mixed layer (OML) is critical for climate and biological systems. Changes in ocean mixed layer depth (MLD) of the Indian Ocean under global warming are examined utilizing outputs from 24 climate models in the Coupled Model Intercomparison Project phase 6 (CMIP6) models and the Community Earth System Model 1.0 with Community Atmosp...

The rapidly enhancing global archive of hydrographic in-situ observations is characterized by a high degree of the data quality heterogeneity. Different data applications (e.g., ocean warming studies) require the development of an automated quality control (QC) system permitting to reliably identify outliers in profile data obtained by different in...

A gridded ocean subsurface salinity dataset with global coverage is useful for research on climate change and its variability. Here, we explore the feed-forward neural network (FFNN) approach to reconstruct a high-resolution (0.25∘ × 0.25∘) ocean subsurface (1–2000 m) salinity dataset for the period 1993–2018 by merging in situ salinity profile obs...

Changes in ocean heat content (OHC) provide a measure of ocean warming, with impacts on the Earth system. This Review synthesizes estimates of past and future OHC changes using observations and models. The top 2,000 m of the global ocean has significantly warmed since the 1950s, gaining 351 ± 59.8 ZJ (1 ZJ = 1021 J) from 1958 to 2019. The rate of w...

The World Climate Research Programme (WCRP) envisions a world “that uses sound, relevant, and timely climate science to ensure a more resilient present and sustainable future for humankind.” This bold vision requires the climate science community to provide actionable scientific information that meets the evolving needs of societies all over the wo...

Since the 1970s, eXpendable BathyThermographs (XBTs) have provided the simplest and most cost-efficient solution for rapid sampling of temperature vs. depth profiles of the upper part of the ocean along ship transects. This manual, compiled by the Ship of Opportunity Program Implementation Panel (SOOPIP) a subgroup of the Global Ocean Observing Sys...

The 2030 Agenda for Sustainable Development provides an ambitious vision for global sustainable development in three dimensions: economic, social and environmental. It has, however, run into major challenges posed by such problems as the lack of data, unbalanced progress, and trade-offs between the Sustainable Development Goals (SDGs). At the same...

Nansen bottle casts served as the main oceanographic instrumentation type for more than a century since the establishing of the technique in the late 1890s. Between the end of the 1960s and the end of the 1990s Nansen cast technique has been gradually replaced by electronic sensor profilers (CTD) . Both instrumentation types are considered as the m...

Climate change is a complex process that exists at the intersection of many human endeavors [...]

The Earth climate system is out of energy balance and heat has accumulated continuously over the past decades, warming the ocean, the land, the cryosphere and the atmosphere. According to the 6th Assessment Report of the Intergovernmental Panel on Climate Change, this planetary warming over multiple decades is human-driven and results in unpreceden...

Patterns of variability in ocean properties are often closely related to large-scale climate pattern indices, and 2021 is no exception. The year 2021 started and ended with La Niña conditions, charmingly dubbed a “double-dip” La Niña. Hence, stronger-than-normal easterly trade winds in the tropical south Pacific drove westward surface current anoma...

A gridded ocean subsurface salinity dataset with global coverage is useful for research on climate change and its variability. Here, we explore a machine learning approach to reconstruct a high-resolution (0.25° × 0.25°) ocean subsurface (0–2000 m) salinity dataset for the period 1993–2018 by merging in situ salinity profile observations with high-...

Recent estimates of the global warming rates suggest that approximately 9% of Earth’s excess heat has been cumulated in the deep and abyssal oceans (below 2000-m depth) during the last two decades. Such estimates assume stationary trends deducted as long-term rates. To reassess the deep ocean warming and potentially shed light on its interannual va...

The ocean's thermal inertia is a major contributor to irreversible ocean changes exceeding time scales that matter to human society. This fact is a challenge to societies as they prepare for the consequences of climate change, especially with respect to the ocean. Here the authors review the requirements for human actions from the ocean's perspecti...

This paper includes a comprehensive assessment of 40 models from the Coupled Model Intercomparison Project phase 5 (CMIP5) and 33 models from the CMIP phase 6 (CMIP6) to determine the climatological and seasonal variation of ocean salinity from the surface to 2000 m. The general pattern of the ocean salinity climatology can be simulated by both the...

The increased concentrations of greenhouse gases in the atmosphere create an increase in Earth’s thermal energy, which is mainly stored in the ocean. Quantification of the rate of increase in ocean heat content (OHC) is vital for understanding the current and future climate of Earth. Linear trend lines have been frequently used to quantify long-ter...

A new approach is taken to estimating the time of death based on cadaver temperatures. The predictions are obtained by using numerical simulation that can be performed in a case‐by‐case scenario. Such a method enables time‐of‐death predictions for persons of any size and weight and in any thermal environment. An added advantage of the method is tha...

The increased concentration of greenhouse gases in the atmosphere from human activities traps heat within the climate system and increases ocean heat content (OHC). Here, we provide the first analysis of recent OHC changes through 2021 from two international groups. The world ocean, in 2021, was the hottest ever recorded by humans, and the 2021 ann...

Framing and Context of the Report Chapter 1 Executive Summary This special report assesses new knowledge since the IPCC 5th Assessment Report (AR5) and the Special Report on Global Warming of 1.5oC (SR15) on how the ocean and cryosphere have and are expected to change with ongoing global warming, the risks and opportunities these changes bring to e...

Numerical simulations have been carried out for gas flow through a horizontal pipe. Accounting is made of buoyancy effects, changes to the thermophysical properties, and the presence of a blockage. It was found that for low-to-moderate Reynolds numbers, the combined effects on heat transfer and pressure loss leads to an improved performance with th...

The quality control (QC) of ocean observational data, essential to establish a high-quality global ocean database, is one of the basic data pre-processing steps in oceanography research, marine monitoring, and forecasting. With the introduction of various advanced instruments in recent decades, oceanographic surveys have expanded from coastal regio...

Salinity plays a vital role in regulating ocean density, stratification and circulation, and is an indicator of the coupling between the ocean, atmosphere and land through the water cycle. This study provides a spatially complete look of the seasonal variation of the upper 2000m ocean salinity from regional to global scales, and assesses the robust...

Global ocean physical and chemical trends are reviewed and updated using seven key ocean climate change indicators: (i) Sea Surface Temperature, (ii) Ocean Heat Content, (iii) Ocean pH, (iv) Dissolved Oxygen concentration (v) Arctic Sea Ice extent, thickness, and volume (vi) Sea Level and (vii) the strength of the Atlantic Meridional Overturning Ci...

Here we provide an overview of some of the most commonly used turbulence models used in current CFD modeling. We compare the governing equations, applications of use, and results between the models. Finally, we provide our own recommendations, based on more than two decades of collaborative research.

This chapter details 2020 global patterns in select observed oceanic physical, chemical, and biological variables relative to long-term climatologies, their differences between 2020 and 2019, and puts 2020 observations in the context of the historical record.

Ocean temperature observations are crucial for a host of climate research and forecasting activities, such as climate monitoring, ocean reanalysis and state estimation, seasonal-to-decadal forecasts, and ocean forecasting. For all of these applications, it is crucial to understand the uncertainty attached to each of the observations, accounting for...

KEYNOTE POINTS 1. Thermal expansion from a warming ocean and land ice melt are the main causes of the accelerating global rise in the mean sea level. 2. Global warming is also affecting many circulation systems. The Atlantic Meridional Overturning Circulation has already weakened and will most likely continue to do so in the future. The impacts o...

Expendable bathythermographs (XBTs) have been widely deployed for ocean monitoring since the late-1960s. Improving the quality of XBT data is a vital task in climatology. Many factors (e.g., temperature, probe type, and manufacturing time) have been identified as major influences of XBT systematic bias. In addition, the recording system (RS) has lo...

The long-term warming of the ocean is a critical indicator of both the past and present state of the climate system. It also provides insights about the changes to come, owing to the persistence of both decadal variations and secular trends, which the ocean records extremely well (Hansen et al., 2011; IPCC, 2013; Rhein et al., 2013; Trenberth et al...

Seawater generally forms stratified layers with lighter waters near the surface and denser waters at greater depth. This stable configuration acts as a barrier to water mixing that impacts the efficiency of vertical exchanges of heat, carbon, oxygen and other constituents. Previous quantification of stratification change has been limited to simple...

The study of energy flows in the Earth system is essential for understanding current climate change. To understand how energy is accumulating and being distributed within the climate system, an updated reconstruction of energy fluxes at the top of atmosphere, surface and within the atmosphere derived from observations is presented. New satellite an...

The Indian Ocean Observing System (IndOOS), established in 2006, is a multinational network of sustained oceanic measurements that underpin understanding and forecasting of weather and climate for the Indian Ocean region and beyond. Almost one-third of humanity lives around the Indian Ocean, many in countries dependent on fisheries and rain-fed agr...

Ocean salinity records the hydrological cycle and its changes, but data scarcity and the large changes in sampling make the reconstructions of long-term salinity changes challenging. Here, we present a new observational estimate of changes in ocean salinity since 1960 from the surface to 2000 m. We overcome some of the inconsistencies present in ex...

Human-induced atmospheric composition changes cause a radiative imbalance at the top of the atmosphere which is driving global warming. This Earth energy imbalance (EEI) is the most critical number defining the prospects for continued global warming and climate change. Understanding the heat gain of the Earth system – and particularly how much and...

The rate of global-mean sea-level rise since 1900 has varied over time, but the contributing factors are still poorly understood¹. Previous assessments found that the summed contributions of ice-mass loss, terrestrial water storage and thermal expansion of the ocean could not be reconciled with observed changes in global-mean sea level, implying th...

Overview—R. Lumpkin In this chapter, we examine the state of the global oceans in 2019, focusing both on changes from 2018 to 2019 and on the longer-term perspective. Sidebars focus on the significant and ongoing scientific results from the growing array of Argo floats measuring biogeochemical properties, and on the OceanObs’19 conference, a once-p...

The current coronavirus pandemic has reached global proportions and requires unparalleled collective and individual efforts to slow its spread. One critically important issue is the proper sterilization of physical objects that have been contaminated by the virus. Here, we review the currently existing literature on thermal inactivation of coronavi...

The importance of a national or regional network of meteorological stations for improving weather predictions has been recognized for many years. Ground-based automatic weather stations typically observe weather at a height of 2–10 m above ground level (AGL); however, these observations may have two major shortcomings. Large portions of data cannot...

A strategy that informs on countries’ potential losses due to lack of climate action may facilitate global climate governance. Here, we quantify a distribution of mitigation effort whereby each country is economically better off than under current climate pledges. This effort-sharing optimizing approach applied to a 1.5 °C and 2 °C global warming t...

A homogeneous, consistent, high-quality in situ temperature data set covering some decades in time is crucial for the detection of climate changes in the ocean. For the period 1940 to present, this study investigates the data quality of temperature profiles from mechanical bathythermographs (MBT) by comparing these data with reference data obtained...

Abstract. Human-induced atmospheric composition changes cause a radiative imbalance at the top-of-atmosphere which is driving global warming. This Earth Energy Imbalance (EEI) is a fundamental metric of climate change. Understanding the heat gain of the Earth system from this accumulated heat – and particularly how much and where the heat is distri...

During the Argo period, the Pacific Ocean as well as the global oceans became saltier in the upper-200 m from 2005 to 2015, with a significant spatial variability. Using Argo-based observations and the Estimating the Circulation and Climate of the Ocean (ECCO), a salinity budget analysis in the upper 200 m was conducted to investigate what controls...

This is the Summary for Policy Makers of the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, as approved by the IPCC member countries at the Plenary in Monaco, 25 September 2019.

Community Paper - Frontiers of Marine Science https://www.frontiersin.org/articles/10.3389/fmars.2019.00432/full

The energy radiated by the Earth toward space does not compensate the incoming radiation from the Sun leading to a small positive energy imbalance at the top of the atmosphere (0.4–1 Wm–2). This imbalance is coined Earth’s Energy Imbalance (EEI). It is mostly caused by anthropogenic greenhouse gas emissions and is driving the current warming of the...

The first eXpendable BathyThermographs (XBTs) were deployed in the 1960s in the North Atlantic Ocean. In 1967 XBTs were deployed in operational mode to provide a continuous record of temperature profile data along repeated transects, now known as the Global XBT Network. The current network is designed to monitor ocean circulation and boundary curre...

Ocean meridional heat transports (MHTs) are deduced as a residual using energy budgets to produce latitude versus time series for the globe, Indo-Pacific, and Atlantic. The top-of-atmosphere (TOA) radiation is combined with the vertically integrated atmospheric energy divergence from atmospheric reanalyses to produce the net surface energy fluxes e...