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1.
利用任意时刻AVHRR资料近似估计区域地表温度日较差的试验 总被引：1，自引：1，他引：1
根据表征土壤温度日变化的土温方程一阶近似解，提出一种利用一日中任意时刻NOAA－AVHRR图像数据估计地表温度日较差的简易推算方法。该方法尤其可用于反演土壤含水量的计算，当图像数据的时次与热惯量法所要求的最高、最低温度时次配不准的情况下，近似地估计地表温度日较差，进而计算地表热惯量及相应的土壤含水量。用实例验证了该方法的可行性，为进一步推广应用奠定基础。 相似文献
2.
E. G. Klimova N. V. Kilanova O. A. Dubrovskaya R. B. Zaripov 《Russian Meteorology and Hydrology》2010,35(9):596-603
The procedure is described of the estimation of statistical structure of short-range forecast errors of temperature field in the atmospheric boundary layer for the purpose of objective analysis. The numerical experiments on the estimation of forecast error covariances were carried out for the WRF (Weather Research and Forecast, NCEP, USA) model. The comparative experiments were implemented on the estimation of the influence of stability type in the atmospheric boundary layer on the variability of vertical and three-dimensional covariances. It is demonstrated that the variance and radius of correlation of temperature field forecast errors along the vertical as well as the variability of three-dimensional covariance functions in the atmospheric boundary layer differ considerably at different stability types. The results are cited of the numerical experiments on the estimation of the WRF model temperature field forecast error covariances in the atmospheric boundary layer for summer and winter periods. 相似文献
3.
用NOAA/AVHRR资料遥感土壤水分时风速的影响 总被引：12，自引：1，他引：11
以热惯量法为基础,在地理信息系统（ＧＩＳ）的支持下,通过计算地形参数Ｒ与Ｆ,间接考虑了风速对用ＮＯＯＡＡ／ＡＶＨＲＲ资料遥感土壤水分的影响。结果表明：考虑风速后,遥感土壤水分的精度比热惯量法有所提高;风速对遥感土壤水分的影响主要限于土壤浅层,到３０ｃｍ深度以下时可以不考虑其影响;遥感土壤水分的最佳深度并不在土壤表层,而在２０ｃｍ深度左右。 相似文献
4.
Summary This paper presents a climatological application of the combination of remote sensing data and multivariate analysis. It proposes a methodology to perform an agroclimatic characterization of a region with the aim of determining homogeneous areas. This methodology is applied to Catalonia, in the northwest of the Mediterranean Sea, in the Iberian Peninsula. To this end various multivariate analysis techniques have been applied to data from 107 meteorological stations and to digitally processed AVHRR images from a NOAA satellite (ground surface temperature and thermal inertia). Values of emissivity and albedo for different land uses and phenomenological states, in addition to the most suitable algorithms for the soil surface temperature, have been obtained. Combining this information with orographic characteristics and the Papadakis classification, a final map is obtained with 68 homogeneous zones for the period between April and October, the most important for the agriculture of the area studied.With 5 Figures 相似文献
5.
This study deals with potential changes in the relative humidity associated with global warming and their implications on
heat stress along the coastal region of the Mediterranean in the summer season. It is based on the assumption that the regional
warming will enhance the lower-level stability due to the thermal inertia of the sea with respect to its overlying air. The
enhanced stability implies more effective trapping of the near surface moisture, and as a result—further increase of the relative
humidity. The marine boundary layer over the Mediterranean is modeled. The central feature of the model is the marine inversion
capping the marine moist air, which intensity is positively correlated with the stability. Simple calculations indicate that
if the temperature increases, while the stability remains unchanged, the near-surface relative humidity would not be affected.
But, an increase in the stability would result in an increase in the near-surface relative humidity. This prediction is validated
through observed trends of the respective fields, using the NCEP/NCAR reanalysis data and soundings from the eastern Mediterranean.
The results are consistent in indicating an increase in the near-surface temperature, the lower-level stability and the relative
humidity over the eastern part of the Mediterranean, but not in its western part. The results for the eastern Mediterranean
support the expectation for an aggravation of heat stress beyond that imparted by the temperature rise. 相似文献
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7.
Solar radiation is an essential and important variable to many models. However, it is measured at a very limited number of meteorological stations in the world. Developing method for accurate estimation of solar radiation from measured meteorological variables has been a focus and challenging task. This paper presents the method of solar radiation estimation using support vector machine (SVM). The main objective of this work is to examine the feasibility of SVM and explore its potential in solar radiation estimation. A total of 20 SVM models using different combinations of sunshine ratio, maximum and minimum air temperature, relative humidity, and atmospheric water vapor pressure as input attributes are explored using meteorological data at 15 stations in China. These models significantly outperform the empirical models with an average 14 % higher accuracy. When sunshine duration data are available, model SVM2 using sunshine ratio and air temperature range is proposed. It significantly outperforms the empirical models with an average 26 % higher accuracy. When sunshine duration data are not available, model SVM19 using maximum temperature, minimum temperature and atmospheric water vapor pressure is proposed. It significantly outperforms the temperature-based empirical models with an average of 18 % higher accuracy. The remarkable improvement indicates that the SVM method would be a promising alternative over traditional approaches for estimation of solar radiation at any locations. 相似文献
8.
Based on three global annual mean surface temperature time series and three Chinese annual mean surface air temperature time series, climate change trends on multiple timescales are analyzed by using the trend estimation method of multi-sliding time windows. The results are used to discuss the so-called global-warming hiatus during 1998–2012. It is demonstrated that different beginning and end times have an obvious effect on the results of the trend estimation, and the implications are particularly large when using a short window. The global-warming hiatus during 1998–2012 is the result of viewing temperature series on short timescales; and the events similar to it, or the events with even cold tendencies, have actually occurred many times in history. Therefore, the global-warming hiatus is likely to be a periodical feature of the long-term temperature change. It mainly reflects the decadal variability of temperature, and such a phenomenon in the short term does not alter the overall warming trend in the long term. 相似文献
9.
用线性模型讨论了对流和加热对重力惯性波的激发，分别讨论了初始垂直速度扰动和初始位温扰动及大气内部加热在静态层结大气中激发的重力惯性波，及重力惯性波过程引起的大气温压场的变化。得到的结果可以帮助理解中小尺度系统的发生发展、对流过程与环境大气的相互作用。 相似文献
10.
Most deliberations on climate policy are based on a mitigation response that assumes a gradually increasing reduction over time. However, situations may occur where a more urgent response is needed. A key question for climate policy in general, but even more in the case a rapid response is needed, is: what are the characteristic response times of the response options, such as rapid mitigation or solar radiation management (SRM)? This paper explores this issue, which has not received a lot of attention yet, by looking into the role of both societal and physical response times. For mitigation, technological and economic inertia clearly limit reduction rates with considerable uncertainty corresponding to political inertia and societies’ ability to organize rapid mitigation action at what costs. The paper looks into a rapid emission reductions of 4–6 % annually. Reduction rates at the top end of this range (up to 6 %) could effectively reduce climate change, but only with a noticeable delay. Temperatures could be above those in the year of policy introduction for more than 70 years, with unknown consequences of overshoot. A strategy based on SRM is shown to have much shorter response times (up to decades), but introduces an important element of risk, such as ocean acidification and the risk of extreme temperature shifts in case action is halted. Above all, the paper highlights the role of response times in designing effective policy strategies implying that a better understanding of these crucial factors is required. 相似文献
11.
R. M. Williams 《Boundary-Layer Meteorology》1977,12(3):299-305
Global estimates of momentum and heat fluxes are required for the application of any general atmospheric and oceanic circulation model. A new technique for the estimation of these fluxes in a constant flux boundary layer is developed. The new approach is a modification of the dissipation technique but the only required measurements are the mean and fluctuating temperatures at two levels within the constant flux layer. All other flux estimation techniques require measurement of both temperature and velocity. Data are presented to compare flux estimation results with the conventional eddy-correlation technique. Also discussed are the limitations of the procedure and restrictions on its applicability. 相似文献
12.
基于FY-2C卫星资料估算四川地面降水方法研究 总被引：4，自引：0，他引：4
应用2006年6月6日00时(北京时)至7日06时四川地区的自动站降水资料和FY-2C静止卫星红外亮温资料,共3854对样本,分析发现1小时内的最低红外亮温和红外亮温增量两因子能很好地表征地面1小时累计降水量,且能有效地进行四川地面1小时降水估算,并由此建立了估算降水方法.通过对2006年8月27日13-19时,2006年8月28日04-16时两个时段估算降水结果的初步检验来看,其均方根差都小于2.0mm,随着最低亮温的增加,其均方根差也越小.由此可见,基于FY-2C静止卫星1小时内最低红外亮温和亮温增量来估算四川地面1小时降水是可行的,且效果较好. 相似文献
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Otávio C. Acevedo Osvaldo L. L. Moraes Gervásio A. Degrazia Luiz E. Medeiros 《Boundary-Layer Meteorology》2006,119(1):41-55
The determination of nocturnal surface fluxes in low wind conditions is a major problem for micrometeorological studies. The
eddy correlation technique, extensively used in field measurements, becomes inappropriate if not enough turbulent activity
exists. At the same time, the phenomenon of turbulence intermittency is responsible for the existence of localized events
of short duration within which a large fraction of the total nighttime scalar exchange occurs. The scalar flux within a certain
intermittent event varies considerably depending on the window used for the flux calculation. In many cases, events with very
different time durations occur in the same night, and therefore, the proper determination of the surface flux would require
averaging within data windows of different sizes for each event. In this work, the surface exchanges of temperature, moisture
and carbon dioxide are analysed at a micrometeorological tower at southern Brazil. Intermittent turbulence is a common occurrence
at the location. The analysis shows that the fluxes vary with turbulence intensity and the estimation technique. A variable-window
size method for flux estimation is suggested and shown to cause an increase in the magnitude of the nocturnal surface fluxes 相似文献
16.
航线飞行温度数据是航线适应性分析、开航分析和飞机选型等研究工作的基础。本文基于NOAA历史气象数据,通过对原始温度数据的统计、分析、拟合,建立与原始温度数据拟合度最高的函数模型,构建基于温度频率密度曲线特征的航路点温度快速估算方法;然后以典型的经纬度网格点为例,将直接统计计算和快速估算方法的计算结果与波音公司WINDTEMP.EXE软件计算结果进行对比,表明基于统计计算的航路点温度估算方法具有准确可靠的优点,但计算速度较慢,难以满足民航运行要求;该论文所研究的基于温度频率密度曲线特征的航路点温度快速估算方法则具有精度高、运算速度快的优点,可以满足民航运行的真实需要。 相似文献
17.
The one-layer radiation atmospheric model with SRB (Surface Radiation Budget) database for 1984-2007 was used to obtain the estimation of variations in the distribution of surface temperature for a case of general increase in atmospheric albedo by 1%, that is, surface temperature decreases by 1°C on average on the globe. 相似文献
18.
《环境影响评价技术导则大气环境》（HJ2.2-2018）推荐的估算模式AERSCREEN在气象和地形资料的处理以及建筑物下洗等多个方面做了改进。利用估算模式AERSCREEN,针对30 m左右高度的点源,进行了不同排放参数、不同气象条件下最大落地浓度的敏感性试验。结果表明：随着烟气出口流速的增大,地面浓度最大值逐渐减小;随着波文比的变化,地面浓度最大值没有明显的变化;随着地面粗糙度的增大,地面浓度最大值逐渐减小;随着烟气出口温度的增高,地面浓度最大值逐渐减小;当烟气温度为75℃,粗糙度达到1.3 m时,地面浓度达到最小;随着反照率的增大,地面浓度最大值逐渐减小;随着烟囱高度的增大,地面浓度最大值逐渐减小;在各种烟囱高度条件下,随着最高环境温度的增高,地面浓度最大值逐渐增大;而在各种环境温度条件下,随着烟囱高度的增高,地面浓度最大值在逐渐减小;模式中,随着最低环境温度的增高,地面浓度最大值没有变化;但随着最小风速的增大,模拟得到的地面浓度最大值会逐渐减小。 相似文献
19.
Vertical wind and air temperature profile related parameters in the surface layer at the edge of suburban area of Zagreb (Croatia) have been considered. For that purpose, adopted Monin–Obukhov similarity theory and a set of observations of wind and air temperature at 2 and 10?m above ground, recorded in 2005, have been used. The root mean square differences (errors) principle has been used as a tool to estimate the effective roughness length as well as standard deviations of wind speed and wind gusts. The results of estimation are effective roughness lengths dependent on eight wind direction sectors unknown before. Gratefully to that achievement, representativeness of wind data at standard 10-m height can be clarified more deeply for an area of at least about 1?km in upwind direction from the observation site. Extrapolation of wind data for lower or higher levels from standard 10-m height are thus properly representative for a wider inhomogeneous suburban area and can be used as such in numerical models, flux and wind energy estimation, civil engineering, air pollution and climatological applications. 相似文献
20.
基于1904—2019年营口市国家气象观测站的气温资料,利用线性倾向估计、7 a滑动平均、Mann-Kendall检验、Morlet小波分析等方法,分析了近116 a营口市气温变化规律和特征。结果表明：1904—2019年,营口市年平均气温呈明显的上升趋势,上升速率为0.17℃·(10 a)-1。各季平均气温变化也均呈现出明显的上升趋势,其中冬季平均气温上升速率最快,春季、秋季次之,夏季上升最为缓慢。营口市年平均气温具有明显的年代际变化特征,大致经历了“冷—暖—冷—暖”的变化过程,各季也呈现出不同的变化过程。营口市年平均气温、春季、夏季、秋季及冬季平均气温均发生了突变,突变的年份分别为1987年、1988年、2015年、1991年和1979年。营口市年平均气温存在6 a、20 a、37 a及64 a的周期震荡,其中64 a为主周期,各季平均气温也存在不同时间尺度的周期震荡。 相似文献