A model for discrimination and prediction of mental workload of aircraft cockpit display interface

With respect to the ergonomic evaluation and optimization in the mental task design of the aircraft cockpit display interface, the experimental measurement and theoretical modeling of mental workload were carried out under flight simulation task conditions using the performance evaluation, subjective evaluation and physiological measurement methods. The experimental results show that with an increased mental workload, the detection accuracy of flight operation significantly reduced and the reaction time was significantly prolonged; the standard deviation of R-R intervals（SDNN） significantly decreased, while the mean heart rate exhibited little change; the score of NASA_TLX scale significantly increased. On this basis, the indexes sensitive to mental workload were screened, and an integrated model for the discrimination and prediction of mental workload of aircraft cockpit display interface was established based on the Bayesian Fisher discrimination and classification method. The original validation and cross-validation methods were employed to test the accuracy of the results of discrimination and prediction of the integrated model, and the average prediction accuracies determined by these two methods are both higher than 85%. Meanwhile, the integrated model shows a higher accuracy in discrimination and prediction of mental workload compared with single indexes. The model proposed in this paper exhibits a satisfactory coincidence with the measured data and could accurately reflect the variation characteristics of the mental workload of aircraft cockpit display interface, thus providing a basis for the ergonomic evaluation and optimization design of the aircraft cockpit display interface in the future.     

广汉机场雷暴的航空气候特征分析

利用1986-1995年十年的地面观测资料,对广汉机场雷暴的年变化、日变化特征及持续时间特点进行了分析,同时分析了产生雷暴的天气系统及环流形势。     

Regional Response of the Climate System to Solar Forcing: The Role of the Ocean

A coupled climate model is used to explore the regional response of the climate system to solar forcing, with emphasis on the role of the ocean. It is shown that both the transient and the equilibrium response of surface temperature to changes in total solar irradiation is smaller over ocean than over land because of the ocean’s large heat capacity and the feedback involving evaporation. Furthermore, the advection of temperature anomalies and changes in ocean currents have an impact on the timing and the geographical distribution of the response. Nevertheless, at regional scales, the response to the forcing is embedded within the large internal variability of the system making the detection and analysis of the forced response difficult. Furthermore, this forced response could imply both changes in the mean state of the system as well as in its variability.     

Recent advances in observations and modeling of the solar ultraviolet and X-ray spectral irradiance

There have been significant, recent advances in understanding the solar ultraviolet (UV) and X-ray spectral irradiance from several different satellite missions and from new efforts in modeling the variations of the solar spectral irradiance. The recent satellite missions with solar UV and X-ray spectral irradiance observations include the X-ray Sensor (XRS) aboard the series of NOAA GOES spacecraft, the Upper Atmosphere Research Satellite (UARS), the SOHO Solar EUV Monitor (SEM), the Solar XUV Photometers (SXP) on the Student Nitric Oxide Explorer (SNOE), the Solar EUV Experiment (SEE) aboard the Thermosphere, Ionosphere, Mesosphere, Dynamics, and Energetics (TIMED) satellite, and the Solar Radiation and Climate Experiment (SORCE) satellite. The combination of these measurements is providing new results on the variability of the solar ultraviolet irradiance throughout the ultraviolet range shortward of 200 nm and over a wide range of time scales ranging from years to seconds. The solar UV variations of flares are especially important for space weather applications and upper atmosphere research, and the period of intense solar storms in October–November 2003 has provided a wealth of new information about solar flares. The new efforts in modeling these solar UV spectral irradiance variations range from simple empirical models that use solar proxies to more complicated physics-based models that use emission measure techniques. These new models provide better understanding and insight into why the solar UV irradiance varies, and they can be used at times when solar observations are not available for atmospheric studies.     

模拟失重对心血管自主神经调节功能的影响

载人航天或模拟失重后，航天员会出现运动能力与立位耐力降低，其发生机理与多种因素的改变有关．为进一步验证这种变化与中枢神经系统调节功能障碍的可能相关，本文研究模拟失重过程中心脏与外周血管自主神经调节功能的动态变化及与卧床后立位耐力降低的关系．结果表明，6名被试者的HRV谱的总功率（TP）及低频（LF）、高频（HF）成份均减少，而LF：HF比值在卧床后期有增大趋势．卧床后HUT初始6min所有被试者心率明显快于卧床前的相应值．说明模拟失重后心脏迷走神经反应与外周血管交感神经活动水平降低，心脏交感神经活动水平逐渐升高．但卧床后HUT时心血管自主神经调节反应基本正常．     

On the Response of the Climate System to Solar Forcing

The climate response to changes in radiative forcing depends crucially on climate feedback processes, with the consequence that solar and greenhouse gas forcing have both similar response patterns in the troposphere. This circumstance complicates significantly the attribution of the causes of climate change. Additionally, the climate system displays a high level of unforced intrinsic variability, and significant variations in the climate of many parts of the world are due to internal processes. Such internal modes contribute significantly to the variability of climate system on various time scales, and thus compete with external forcing in explaining the origin of past climate extremes. This highlights the need for independent observations of solar forcing including long-term consistent observational records of the total and spectrally resolved solar irradiance. The stratospheric response to solar forcing is different from its response to greenhouse gas forcing, thus suggesting that stratospheric observations could offer the best target for the identification of the specific influence of solar forcing on climate.     

Deriving a sea surface temperature record suitable for climate change research from the along-track scanning radiometers

We describe the approach to be adopted for a major new initiative to derive a homogeneous record of sea surface temperature for 1991–2007 from the observations of the series of three along-track scanning radiometers (ATSRs). This initiative is called (A)RC: (Advanced) ATSR Re-analysis for Climate. The main objectives are to reduce regional biases in retrieved sea surface temperature (SST) to less than 0.1 K for all global oceans, while creating a very homogenous record that is stable in time to within 0.05 K decade⁻¹, with maximum independence of the record from existing analyses of SST used in climate change research. If these stringent targets are achieved, this record will enable significantly improved estimates of surface temperature trends and variability of sufficient quality to advance questions of climate change attribution, climate sensitivity and historical reconstruction of surface temperature changes. The approach includes development of new, consistent estimators for SST for each of the ATSRs, and detailed analysis of overlap periods. Novel aspects of the approach include generation of multiple versions of the record using alternative channel sets and cloud detection techniques, to assess for the first time the effect of such choices. There will be extensive effort in quality control, validation and analysis of the impact on climate SST data sets. Evidence for the plausibility of the 0.1 K target for systematic error is reviewed, as is the need for alternative cloud screening methods in this context.     

Earth weather and climate control: can space technology contribute?

With ongoing progress in space technology, questions of its potential for the modification of weather and climate phenomena (often summarized by the term ‘geoengineering’) ranging from small-scale severe weather events to mitigation of effects caused by global climate change and ozone depletion have become popular. This paper reviews the current state of scientifically based studies in this context and attempts to provide a basis for an assessment of geoengineering efforts with respect to technological, economic and fundamental scientific aspects. The overview indicates that the current state of knowledge about climate variability as a consequence of natural and anthropogenic influences is sufficient to classify geoengineering solutions as highly risky and their consequences as extremely difficult to predict. Even on smaller scales and with less complexity of interacting processes, only very limited boundary conditions, i.e. a narrow range of atmospheric variability and land surface topography favouring the intended alteration, seem to justify weather modification. Moreover, as for systems reaching scales of large organized storms and hurricanes, required energy and control resources are well beyond existing capabilities. Consequently, the use of space technology for provision of better information on environmental change and integration of remote sensing data into weather and climate models forecasts is supported.     

Surface temperatures at the nearside of the Moon as a record of the radiation budget of Earth’s climate system

Understanding the balance between incoming radiation from the Sun and outgoing radiation from Earth is of critical importance in the study of climate change on Earth. As the only natural satellite of Earth, the Moon is a unique platform for the study of the disk-wide radiation budget of Earth. There are no complications from atmosphere, hydrosphere, or biosphere on the Moon. The nearside of the Moon allows for a focus on the solar radiation during its daytime, and on terrestrial radiation during its nighttime. Additionally, lunar regolith temperature is an amplifier of the terrestrial radiation signal because lunar temperature is proportional to the fourth square root of radiation as such is much more sensitive to the weak terrestrial radiation in nighttime than the strong solar radiation in daytime. Indeed, the long-term lunar surface temperature time series obtained inadvertently by the Heat Flow Experiment at the Apollo 15 landing site three decades ago may be the first important observation from deep space of both incoming and outgoing radiation of the terrestrial climate system. A revisit of the lunar surface temperature time series reveals distinct characteristics in lunar surface daytime and nighttime temperature variations, governed respectively by solar and terrestrial radiation.     

时标偏差对站间双向时间比对的影响分析

基于站间双向时间比对的基本原理,讨论了时标偏差对站间双向时间比对精度的影响,并利用实测的站间双向测距值,计算比较了存在不同时标偏差情况下站间双向时间比对的结果和精度。结果表明:时标偏差影响体现的是伪距变率项和伪距径向加速度项;当时标偏差不大于1 s时,时标偏差影响主要体现的是伪距变率项;时标偏差符号相反时,对站间双向时间比对结果的影响大小一致,符号相反;时标偏差越大,对站间双向时间比对结果的影响越大。