Moisture Changes in the Northern Xinjiang Basin Over the Past 2400 years as Documented in Pollen Records of Jili Lake

Regional humidity is important for terrestrial ecosystem development, while it differs from region to region in inland Asia, knowledge of past moisture changes in the lower basin of northern Xinjiang remainly largely unclear. Based on a pollen record from Jili Lake, the Artemisia/(Amaranthaceae + Ephedra) (Ar/(Am + E)) ratio, as an index of regional humidity, has recorded four relatively dry phases: 1) 400 BCE to 1 CE, 2) the Roman Warm Period (RWP; c. 1–400 CE), 3) the Medieval Warm Period (MWP; c. 850–1200 CE) and 4) the Current Warm Period (CWP; since 1850 CE). In contrast, the Dark Age Cold Period (DACP; c. 400–850 CE) and the Little Ice Age (LIA; c. 1200–1850 CE) were relatively wet. Lower lake levels in a relatively humid climate background indicated by higher aquatic pollen (Typha and Sparganium) after c. 1700 CE are likely the result of intensified irrigation for agriculture in the catchment as documented in historical records. The pollen Ar/(Am + E) ratio also recorded a millennial-scale wetting trend from 1 CE to 1550 CE which is concomitant with a long-term cooling recorded in the Northern Hemisphere.

Transient Climate Simulations of Orbital Effects on Mesozoic Climates

<p>The Mesozoic era (~252—66 Ma) is traditionally considered as a prolonged greenhouse period, witnessing the breakup of the Pangaean supercontinent. Orbital cycles have, for example, been invoked as drivers of e.g. Pangaean „Megamonsoon“ variability and eustatic sea level cycles in the Mesozoic.</p><p>We aim to contribute to a more comprehensive understanding of orbital effects on Mesozoic climates by employing the newly developed CLIMBER-X Earth System Model. Here, we primarily use its coupled atmosphere, ocean, sea ice and vegetation modules, but also include preliminary tests with dynamic carbon cycle and ice-sheets. We present first results from a set of transient climate simulations of four Mesozoic timeslices representative for Triassic, Jurassic, Early Cretaceous and Late Cretaceous boundary conditions (e.g. paleogeography and solar luminosity). The simulations each cover ~100,000 years and are driven by changing precession, obliquity, and eccentricity.</p><p>We would like to use the opportunity to discuss this approach and associated questions with the community. For example: Would changing paleogeography and climate background state have modified the response to orbital forcings? Could eustatic sea level cycles have been caused by orbitally-driven redistribution of water between the ocean and land water storages or should orbitally-forced ice sheets also have played a role in the alleged Mesozoic greenhouse? Which connections can be established to proxy records?</p>

Meteorology Open Application Platform (MOAP3.0) -- the Application and Implementation of Brand-new Intelligent Analysis Meteorological Platform

<p><span>The implementation of Intellectualized Analysis Meteorological Platform is based on the Meteorology Open Application Platform (MOAP3.0),which developed by the National Meteorological Centre of China Meteorological Administration. This visualization analysis network platform integrates the main characteristics of statistical analysis, intelligent interaction, and rendering method and uses decoupling development mode. Its Web-Server deployed on distributed cloud framework in a distributed environment, which can support real-time analysis, interactive analysis and visualization analysis of massive meteorological data. The data are including national meteorological observation data, national guidance forecast data (0.05° x 0.05°), the area of forecast, MICAPS data, etc. It has been put into operation since December 2019. According to the results of continual tests, it indicates that the entire system is quite stable, reliable, with second-grade responding time in data transmission. The whole system adopts the design of "one key linkage" and " drilling-down analysis of a temporal and spatial context step by step " , finalizes three main home pages of "disaster analysis", "meteorological big data for living analysis" and "station’s climate background analysis", involves in 36 standard interfaces ,and sets up 21 independent functional modules. In the spatial dimension, the cascading of six spatial levels of meteorological data is followed by observing data, grid data, urban, river basins, regional meteorological centers and national meteorological centers. In the time dimension, the linkage analysis of minute, hour, daily, ten-day periods, monthly value, and annual value completes the full time chain. Theoretically, the integration analysis of history- reality- forecast in China is realized basing on the whole station climate background and a relatively well-developed analysis system of meteorological spatial-temporal data mining. To be specific, the basic meteorological algorithms including in the background of the system are regional average value, precipitation days of different magnitude, historical extremes of single meteorological element, spatial interpolation, fall area analysis, etc. The web-visualization functions contain the online rendering of weather map, spatial-temporal integration display of multiple meteorological elements, color scale classification and filtering, etc. At the same time, in order to solve the problems of dense site in daily operation, the strategies of site thinning and hierarchical rendering are used to optimize. In conclusion, the whole system takes the standardized tile-type electronic map in China as the carrier, displays and interacts the massive meteorological data of various dimensions and types, and finally carries out a complete real-time sequence analysis product, which will be playing an important role in the practical application of forecasting and early warning system of Chinese meteorological fields.</span></p>

Quantifying the Effects of Long-Term Climate Change on Tropical Cyclone Rainfall Using a Cloud-Resolving Model: Examples of Two Landfall Typhoons in Taiwan

To quantify the effects of long-term climate change on typhoon rainfall near Taiwan, cloud-resolving simulations of Typhoon (TY) Sinlaku and TY Jangmi, both in September 2008, are performed and compared with sensitivity tests where these same typhoons are placed in the climate background of 1950–69, which is slightly cooler and drier compared to the modern climate of 1990–2009 computed using NCEP–NCAR reanalysis data. Using this strategy, largely consistent responses are found in the model although only two cases are studied. In control experiments, both modern-day typhoons yield more rainfall than their counterpart in the sensitivity test using past climate, by about 5%–6% at 200–500 km from the center for Sinlaku and roughly 4%–7% within 300 km of Jangmi, throughout much of the periods simulated. In both cases, the frequency of more-intense rainfall (20 to >50 mm h−1) also increases by about 5%–25% and the increase tends to be larger toward higher rain rates. Results from the water budget analysis, again quite consistent between the two cases, indicate that the increased rainfall from the typhoons in the modern climate is attributable to both a moister environment (by 2.5%–4%) as well as, on average, a more active secondary circulation of the storm. Thus, a changing climate may already have had a discernible impact on TC rainfall near Taiwan. While an overall increase in TC rainfall of roughly 5% may not seem large, it is certainly not insignificant considering that the long-term trend observed in the past 40–50 yr, whatever the causes might be, may continue for many decades in the foreseeable future.