First Global Carbon Dioxide Maps Produced from Tan Sat Measurements

1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide（CO2 ）is the main greenhouse gas involved in heating the troposphere.However,the poor availability of global CO2 measurements makes it difficult to estimate CO2 emissions accurately.

Atmospheric Profiling Synthetic Observation System in Tibet

1. Introduction The Atmosphere Profiling Synthetic Observation System （APSOS） is the first ground-based facility for profiling atmospheric variables and multiple constituents in the whole （neutral） atmosphere from the surface up to the lower thermosphere. It enables simultaneous observations and extensive studies of the atmospheric vertical structure and constituent transport.

Comparison of Beijing MST Radar and Radiosonde Horizontal Wind Measurements

To determine the performance and data accuracy of the 50 MHz Beijing Mesosphere-Stratosphere-Troposphere （MST） radar, comparisons of radar measured horizontal winds in the height range 3-25 km with radiosonde observations were made during 2012. A total of 427 profiles and 15 210 data pairs were compared. There was very good agreement between the two types of measurement. Standard deviations of difference （mean difference） for wind direction, wind speed, zonal wind and meridional wind were 24.86° （0.77°）, 3.37 （-0.44）, 3.33 （-0.32） and 3.58 （-0.25） m s^-1, respectively. The annual standard deviations of differences for wind speed were within 2.5-3 m s^-1 at all heights apart from 10-15 km, the area of strong winds, where the values were 3-4 m s^-1. The relatively larger differences were mainly due to wind field variations in height regions with larger wind speeds, stronger wind shear and the quasi-zero wind layer. A lower MST radar SNR and a lower percentage of data pairs compared will also result in larger inconsistencies. Importantly, this study found that differences between the MST radar and radiosonde observations did not simply increase when balloon drift resulted in an increase in the real-time distance between the two instruments, but also depended on spatiotemporal structures and their respective positions in the contemporary synoptic systems. In this sense, the MST radar was shown to be a unique observation facility for atmospheric dynamics studies, as well as an operational meteorological observation system with a high temporal and vertical resolution.

A multi-location joint field observation of the stratosphere and troposphere over the Tibetan Plateau

The unique geographical location and high altitude of the Tibetan Plateau can greatly influence regional weather and climate.In particular, the Asian summer monsoon(ASM) anticyclone circulation system over the Tibetan Plateau is recognized to be a significant transport pathway for water vapor and pollutants to enter the stratosphere. To improve understanding of these physical processes, a multi-location joint atmospheric experiment was performed over the Tibetan Plateau from late July to August in 2018, funded by the fiveyear(2018–2022) STEAM(stratosphere and troposphere exchange experiment during ASM) project, during which multiple platforms/instruments—including long-duration stratospheric balloons, dropsondes, unmanned aerial vehicles, special sounding systems, and ground-based and satellite-borne instruments—will be deployed. These complementary methods of data acquisition are expected to provide comprehensive atmospheric parameters(aerosol, ozone, water vapor, CO_2, CH_4, CO, temperature, pressure,turbulence, radiation, lightning and wind); the richness of this approach is expected to advance our comprehension of key mechanisms associated with thermal, dynamical, radiative, and chemical transports over the Tibetan Plateau during ASM activity.

The Impact of Cut-off Lows on Ozone in the Upper Troposphere and Lower Stratosphere over Changchun from Ozonesonde Observations

In situ measurements of the vertical structure of ozone were made in Changchun （43.53°N, 125.13°E）, China, by the Institute of Atmosphere Physics, in the summers of 2010-13. Analysis of the 89 validated ozone profiles shows the vari- ation of ozone concentration in the upper troposphere and lower stratosphere （UTLS） caused by cut-off lows （COLs） over Changchun. During the COL events, an increase of the ozone concentration and a lower height of the tropopause are observed. Backward simulations with a trajectory model show that the ozone-rich airmass brought by the COL is from Siberia. A case study proves that stratosphere-troposphere exchange （STE） occurs in the COL. The ozone-rich air mass transported from the stratosphere to the troposphere first becomes unstable, then loses its high ozone concentration. This process usually happens during the decay stage of COLs. In order to understand the influence of COLs on the ozone in the UTLS, statistical analysis of the ozone profiles within COLs, and other profiles, are employed. The results indicate that the ozone concentrations of the in-COL profiles are significantly higher than those of the other profiles between ±4 km around the tropopause. The COLs induce an increase in UTLS column ozone by 32% on average. Meanwhile, the COLs depress the lapse-rate tropopause （LRT）/dynamical tropopause height by 1.4/1.7 km and cause the atmosphere above the tropopause to be less stable. The influence of COLs is durable because the increased ozone concentration lasts at least one day after the COL has passed over Changchun. Furthermore, the relative coefficient between LRT height and lower stratosphere （LS） column ozone is -0.62, which implies a positive correlation between COL strength and LS ozone concentration.

Preface

Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO)was established in 1995and became one of the Key Laboratory of Chinese Academy of Sciences(CAS)in 2008.LAGEO emphasizes both fundamental research and high-tech research and development,and sets the major research directions as middle atmosphere and global environmental observation,which include the following four aspects:1)

Application of cloud multi-spectral radiances in revealing cloud physical structures

The radiances scattered or emitted by clouds demonstrate diverse features at different wavelengths due to different cloud physical structures. This paper presents a method(the smallest-radiance-distance method, SRaDM) of revealing the physical structures of clouds. The method is based on multi-spectral radiances measured by the Moderate Resolution Imaging Spectroradiometer(MODIS)onboard Aqua. The principle and methodology of SRaDM is deduced and provided in this paper. Correlation analysis based on data from MODIS and Cloud Profiling Radar(onboard CloudSat), collected from January 2007 to December 2010 over an ocean area(15°N–45°N,145°E–165°E), led to selection of radiances at 13 wavebands of MODIS that demonstrated high sensitivity to cloud physical structures;radiances at the selected wavebands were subjected to SRaDM. The Standardized Euclidean distance is introduced to quantify the degree of changes in multi-spectral radiances(termed D_(rd)) and in physical structures(termed D_(st)) between cloud profiles. Statistics based on numerous cloud profiles show that D_(rd) decreases monotonically with a decrease in D_(st), which implies that small D_(rd) always accompanies small D_(st). According to the law of D_(rd) and D_(st), the new method, SRaDM, for revealing physical structures of clouds from the collocation of cloud profiles of similar multi-spectral radiances, is presented. Then, two successful experiments are presented in which cloud physical structures are captured using multi-spectral radiances. SRaDM provides a way to obtain knowledge of the physical structures of clouds over relatively larger areas, and is a new approach to obtaining 3D cloud fields.

Retrievals of over-ocean precipitable water from SSM/I by SOM network model

An SOM network model was developed for retrievals of the oceanic total precipitable water (PW) from the SSM/I, by using the SSM/I and radiosonde observation data set provided by the NASDA (Japan). The model was first trained by 5/6 of the data, and the other data were used to test the retrieval ability of the model. The retrieval results showed that the SOM network model was better than the routine operational algorithm.