太阳能光伏发电量预报方法的发展

太阳能光伏发电技术成为当今世界可再生能源发电领域的一个研究热点。在未来,我国大规模的并网光伏发电系统将持续快速发展,但目前我国对太阳能光伏发电量预报方法的研究还很薄弱,几乎没有可满足实际太阳能光伏发电量预报需求的方法和系统。太阳能光伏发电量预报,主要是通过太阳总辐射的准确预报,结合光伏电站历史发电量数据分析,进而得到光伏发电量预报。通过对国内外太阳能光伏发电量预报方法的介绍和分类,以及对国际上太阳能光伏发电量预报系统建设的介绍,希望对我国太阳能光伏发电量预报系统发展起到一定的促进和推动作用。     

Analysis of an oasis microclimate in China’s hyperarid zone

The microclimate of a desert oasis in China’s hyperarid zone was monitored, analysed and compared to that of nearby forested lands. Factors associated with differences in photosynthetically active radiation (PAR) between clear, cloudy and dust storm days are discussed. Desert oases were shown to fulfill ecological functions such as altering solar radiation, adjusting near-ground and land surface temperatures, reducing temperature differences, lowering wind velocity, and increasing soil and atmospheric humidity. Total solar radiation within the oasis was roughly half that above the forest canopy. During the growing season, air temperatures in Populus euphratica Olivier and Tamarix ramosissima Ledeb. woodlands were, on average, 1.62 and 0.83°C lower, respectively, than that in surrounding woodlands. The greater the forest cover, the greater was the difference in temperature. Air temperature was higher at the upper storey than that at the lower storey of the community, i.e., air temperature increased with increasing height above the soil surface. During the growing season, relative humidity was higher in woodlands than in surrounding areas: relative humidity in P. euphratica and T. ramosissima woodlands were, on average, 8.5 and 4.2% higher, respectively, than that in the surrounding area. Mean wind velocity in the P. euphratica forest land was 0.33 m/s, 2.31 m/s lower than that in the surrounding area. On dust storm days PAR and total radiation, Q, were significantly lower than that on cloudy or clear days. Their ratio, η _Q  = PAR/Q, was larger and much more variable on dust storm days than that on clear or cloudy days.     

Current and future impacts of ultraviolet radiation on the terrestrial carbon balance

One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth’s surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.     

西藏建筑节能设计标准的探讨

做好建筑节能工作,是落实科学发展观,建设节约型社会和节约型城镇的重要举措,也是现代建筑技术发展的方向。把太阳能开发利用作为一个重点,利用太阳能解决冬季采暖和四季生活热水供应,以减少建筑能耗,发展城乡节能建筑体系,是西藏建筑节能设计标准的一个重要宗旨。希望能给在建筑领域里工作的同志们一点启示。     

基于DEM的山地总辐射模型及实现

总辐射状况是决定山地气候的主导性因子。山区地形条件复杂,总辐射分布差异显著,为了便于研究山区总辐射的地域分布规律,该文建立了一种基于DEM模拟山区总辐射的方法,通过提取数字坡度模型、数字高度模型以及地形遮蔽度模型等信息,并采用多层面复合分析的方法,建立了山区直接辐射、散射辐射以及总辐射的数字模型。实验证明,太阳总辐射及其分量在山区中有很强的地域分布规律。该方法采用的DEM精度高,能够精细地反映太阳辐射的地区分布差异,为山地气候资源调查与利用、生态环境建设乃至精细农业的实施提供重要依据。     

基于DEM的黄河流域天文辐射空间分布

Based on the developed distributed model for calculating astronomical solar radiation (ASR), monthly ASR with a resolution of 1 km× 1 km for the rugged terrains of Yellow River Basin was calculated, with DEM data as the general characterization of terrain. This model gives an all-sided consideration on factors that influence the ASR. Results suggest that (1) Annual ASR has a progressive decrease trend from south to north; (2) the magnitude order of seasonal ASR is: summer＞spring＞autumn＞winter; (3) topographical factors have robust effect on the spatial distribution of ASR, particularly in winter when a lower sun elevation angle exists; (4) the ASR of slopes with a sunny exposure is generally 2 or 3 times that of slopes with a shading exposure and the extreme difference of ASR for different terrains is over 10 times in January; (5) the spatial differences of ASR are relatively small in summer when a higher sun elevation angle exists and the extremedifference of ASR for different terrains is only 16% in July; and (6) the sequence of topographical influence strength is: winter＞autumn＞spring＞summer.     

A scheme for pixel-scale aerodynamic surface temperature over hilly land

Hilly-land satellite pixel-scale aerodynamic surface temperatures (AdST) are investigated using LAS (Large Aperture Scintillometer) and meteorological observations during 21-22 May 2001, indicating that the calculated temperatures are predominantly subject to estimated roughness lengths and, to a less extent, to estimated Bowen ratios, with errors to within 3.0 K between the AdST calculations and hilly radiometric surface temperatures retrieved from satellite data with the split window model. The errors depend heavily on the model used and the zenith angles and azimuth of the satellite and sun with respect to the observational site.     

Upgrading of some instrumentation devoted to increase space radiation environment understanding

Three methods permitting to characterize space and onboard spacecraft radiation environment have been developed and/or upgraded in our laboratories: MDU equipment with a semiconductor detector as sensitive element devoted to register energy deposition spectra in the Si-diode; a spectrometer of the linear energy transfer (LET) based on chemically etched polyallyldiglycolcarbonate (PADC) track etch detectors (TED); and thermoluminescent detectors (TLDs) with different dependences of relative TL yield on the LET of particles transferring their energy in them.We have used all these types of dosimetry equipments onboard spacecrafts since several years and succeeded to treat directly read data in terms of both quantitative and qualitative dosimetry characteristics and deduce from them related radiation risk.During last few years all these three types of detectors have been intensely studied to understand still better their possibilities to characterize space radiation fields. Particularly:

1.

Both PADC TED LET spectrometer and TLDs have been exposed in heavier ion beams with LET in water ranging from 1 to about 700 keV/μm with the goal to upgrade their calibration curves;

2.

A new method of MDU directly read data has been developed, permitting to measure not only dose in Si-detector, but also to estimate radiation protection quantities and the neutron contribution to the onboard exposure level;

3.

All three methods have been tested onboard spacecrafts during several missions.

Contribution presents, analyses and discusses the results obtained in items 1-3 and, also, the possibilities of these detectors to help in characterizing radiation fields during longer space missions, above 1 year.     

X-ray flares, plateaus and chromatic breaks of GRB afterglows from up-scattered forward-shock emission

Scattering of the forward-shock synchrotron emission by a relativistic outflow located behind the leading blast wave may produce an X-ray emission brighter than that coming directly from the forward shock and may explain four features displayed by Swift X-ray afterglows: flares, plateaus (slow decays), chromatic light-curve breaks and fast post-plateau decays. For a cold scattering outflow, the reflected flux overshines the primary one if the scattering outflow is nearly baryon-free and highly relativistic. These two requirements can be relaxed if the scattering outflow is energized by weak internal shocks, so that the incident forward-shock photons are also inverse-Compton scattered, in addition to bulk scattering. Sweeping-up of the photons left behind by the forward shock naturally yields short X-ray flares. Owing to the boost in photon energy produced by bulk scattering, the reflected emission is more likely to overshine that coming directly from the forward shock at higher photon energies, yielding light-curve plateaus and breaks that appear only in the X-ray. The brightness, shape and decay of the X-ray light-curve plateau depend on the radial distribution of the scatterer's Lorentz factor and mass flux. Chromatic X-ray light-curve breaks and sharp post-plateau decays cannot be accommodated by the direct forward-shock emission and argue in favour of the scattering-outflow model proposed here. On the other hand, the X-ray afterglows without plateaus, those with achromatic breaks and those with very long lived power-law decays are more naturally accommodated by the standard forward-shock model. Thus, the diversity of X-ray light curves arises from the interplay of the scattered and direct forward-shock emissions.