胡萝卜系列杂交品种

针对我国胡萝卜市场迅速发展的需要,北京市蔬菜研究中心培育出了系列胡萝卜杂交种,现介绍如下: (1)京红五寸(F1)黑田五寸类杂交种,生育期100天,中早熟,三红品种,根长18～20厘米,径粗5～6厘米,柱形,品质好,抗病性强,产量高,亩产5000千克以上,适合我国夏秋季栽培.

Temporal Variations of the Frontal and Monsoon Storm Rainfall during the First Rainy Season in South China

The temporal variations in storm rainfall during the first rainy season (FRS) in South China (SC) are investigated in this study. The results show that the inter-annual variations in storm rainfall during the FRS in SC seem to be mainly influenced by the frequency of storm rainfall, while both frequency and intensity affect the inter-decadal variations in the total storm rainfall. Using the definitions for the beginning and ending dates of the FRS, and the onset dates of the summer monsoon in SC, the FRS is further divided into two sub-periods, i.e., the frontal and monsoon rainfall periods. The inter-annual and inter-decadal variations in storm rainfall during these two periods are investigated here. The results reveal a significant out-of-phase correlation between the frontal and monsoon storm rainfall, especially on the inter-decadal timescale, the physical mechanism for which requires further investigation.

Spatio-temporal Variation of Arctic Sea Ice in Summer from 2003 to 2013

The variation in Arctic sea ice has significant implications for climate change due to its huge influence on the global heat balance. In this study, we quantified the spatio-temporal variation of Arctic sea ice distribution using Advanced Microwave Scanning Radiometer(AMSR-E) sea-ice concentration data from 2003 to 2013. The results found that, over this period, the extent of sea ice reached a maximum in 2004, whereas in 2007 and 2012, the extent of summer sea ice was at a minimum. It declined continuously from 2010 to 2012, falling to its lowest level since 2003. Sea-ice extent fell continuously each summer between July and mid-September before increasing again. It decreased most rapidly in September, and the summer reduction rate was 1.35 × 10~5 km^2/yr, twice as fast as the rate between 1979 and 2006, and slightly slower than from 2002 to 2011. Area with >90% sea-ice concentration decreased by 1.32 × 10~7 km^2/yr, while locations with >50% sea-ice concentration, which were mainly covered by perennial ice, were near the North Pole, the Beaufort Sea, and the Queen Elizabeth Islands. Perennial Arctic ice decreased at a rate of 1.54 × 10~5 km^2 annually over the past 11 years.

Fracture energy evaluation on 7075-T651 aluminum alloy welds determined by instrumented impact pendulum

By using an instrumented impact pendulum, the force versus time curves of 7075-T651 aluminum welds were obtained from standard Charpy-V samples. Considering the force-time curves and constant impact velocity, the fracture energies for different zones were quantified. A fracture energy improvement for the HAZ(33.6 J) was observed in comparison with the weld metal(7.88 J), and base metal(5.37 J and 7.37 J for longitudinal and transverse directions, respectively). This toughness increment was attributed to the microstructural transformation caused by the thermodynamic instability of η′ precipitates during the welding. Fracture energy for weld metal was higher than that for base metal, probably due to pores created during solidification. Regarding the dynamic yielding force obtained from the force-time curves, an approximation to the dynamic yield strength for weld, HAZ and base metal was determined. Fracture surfaces revealed an intergranular failure for base metal in longitudinal direction, whereas a predominately brittle failure(cleavage) with some insights of ductile characteristics was observed for the transverse direction. In contrast, a ductile failure was observed for weld metal and HAZ.

An Effective Approach for Improving the Real-Time Prediction of Summer Rainfall over China

This paper has two purposes. One is to evaluate the ability of an atmospheric general circulation model (IAP9L-AGCM) to predict summer rainfall over China one season in advance. The other is to propose a new approach to improve the predictions made by the model. First, a set of hindcast experiments for summer climate over China during 1982-2010 are performed from the perspective of real-time prediction with the IAP9L-AGCM model and the IAP ENSO prediction system. Then a new approach that effectively combines the hind-cast with its correction is proposed to further improve the model's predictive ability. A systematic evaluation reveals that the model's real-time predictions for 41 stations across China show significant improvement using this new approach, especially in the lower reaches between the Yellow River and Yangtze River valleys.

Detecting the Relationship Between Summer Rainfall Anomalies in Eastern China and the SSTA in the Global Domain with a New Significance Test Method

It is suggested that the multiple samples in a correlation map or a set of correlation maps should be examined with significance tests as per the Bernoulli probability model. Therefore, both the contemporaneous and lag correlations of summertime precipitation R in any one of the three regions of Northern China （NC）, the Changjiang-Huaihe River Valley （CHRV）, and Southern China （SC） with the SSTA in the global domain have been tested in the present article, using our significance test method and the method proposed by Livezey and Chen （1983） respectively. Our results demonstrate that the contemporaneous correlations of sum- mer R in CHRV with the SSTA are larger than those in NC. Significant correlations of SSTA with CHRV R are found to be in some warm SST regions in the tropics, whereas those of SSTA with NC R, which are opposite in sign as compared to the SSTA-CHRVR correlations, are found to be in some regions where the mean SSTs are low. In comparison with the patterns of the contemporaneous correlations, the 1 to 12 month lag correlations between NC R and SSTA, and those between CHRV summer R and SSTA show similar patterns, including the magnitudes and signs, and the spatial distributions of the coefficients. However, the summer rainfall in SC is not well correlated with the SSTA, no matter how long the lag interval is. The results derived from the observations have set up a relationship frame connecting the precipitation anomalies in NC, CHRV, and SC with the SSTA in the global domain, which is critically useful for our understanding and predicting the climate variabilities in different parts of China. Both NC and CHRV summer R are connected with E1 Nifio events, showing a ‘- -＇pattern in an E1 Nifio year and a‘＋ ＋＇ pattern in the subsequent year. Key words summer precipitation; eastern China; global sea surface

Definition of the South China Sea summer monsoon onset

We analyze statistically different definitions of the South China Sea summer monsoon(SCSSM) onset are to establish a SCSSM onset time series that is more recognizable by a majority of indicators.With the acknowledged index,we determine a key area(105°E-112.5°E,7.5°N-12.5°N) and define the zonal wind component in this key area as a new SCSSM onset index,using daily mean reanalysis data of the National Center for Environmental Prediction/National Center for Atmospheric Research.The atmospheric circulations before and after the onset of the SCSSM determined using the index defined in this paper are preliminarily studied.Results show that the Somalia cross-equatorial flow is enhanced,the strongest westerly wind in the tropical Indian Ocean shifts northward,the cyclone couple in the Bay of Bengal and the Southern Hemisphere weaken and move eastward,convection over the South China Sea increases,and the subtropical high retreats from the South China Sea after the outbreak of the SCSSM.By analyzing the atmospheric circulation,it is found that in 1984 and 1999,the SCSSM broke out in pentads 29 and 23,respectively,which is consistent with the onset times determined using our index.

Impact of Preceding Summer North Atlantic Oscillation on Early Autumn Precipitation over Central China

This study examined the impact of the preceding boreal summer(June–August) North Atlantic Oscillation(NAO) on early autumn(September) rainfall over Central China(RCC). The results show that a significant positive correlation exists between the preceding summer NAO and the early autumn RCC on the interannual timescale. In order to understand the physical mechanism between them, the role of ocean was investigated. It was found that the strong summer NAO can induce a tripole sea surface temperature anomaly(SSTA) in the North Atlantic; this SSTA pattern can persist until early autumn. The diagnostic analysis showed that the tripole SSTA pattern excites a downstream Atlantic-Eurasian(AEA) teleconnection, which contributes to an increase in RCC. The circulation anomalies related to SSTA caused by the weak NAO are opposite, so the RCC is less than normal. The results imply that the preceding summer NAO may be regarded as a forecast factor for the early autumn RCC.

Optimisation of Climate Robust Buildings under Summer Conditions with ＂Primero-Comfort＂ Simulation Software Including Detailed User Behaviour and Comfort Expectance

In this paper the possibilities for avoiding active air conditioning by all means of the room itself （window size, glazing, shading system, natural ventilation, and furniture）, artificial light and control strategy of these systems are investigated. A very important component of the system is the user with his ability to adapt to changing conditions in his surrounding and with his possibilities to manipulate the window, the shading system, the light switch etc. All these aspects interact together. It is necessary to optimize them simultaneously. But real planning often separates them into single sections. Simulation tools also handle normally only one or a few aspects, we know for example the thermal simulation or the daylight simulation. Primero-Comfort （2009） is a simulation tool based on energy＋, what is able to consider thermal simulation as well as daylight simulation as well as user behaviour in regard to the probability of window openings. The resulting thermal comfort is rated by an adaptive comfort model, the Dutch ISSO 74 （2004）. This allows designing office rooms more realistic. And it shows that an optimized solution has to include the interactions of aU mentioned aspects. Investigations with Primero-Comfort for a moderate European climate （Hamburg） show that a very good comfort can be reached only by passive means of building design also for hot summer weather just like the summer in the year 2003. The keys for such hot-summer-robust-buildings are night ventilation with height difference, heat protection glazing and good shading system, reduced internal heat gains for artificial light by accepting a threshold of 300 lx of daylight as comfortable and a reduced window size oriented on daylighting and the view out of the window.

从孔子的“行夏之时”主张看中国古代四季的划分

商代和西周早期将一年粗疏地划分为春、秋二季,西周后期在二时制的基础上进一步将一年划分为四季。但由于季节逐渐与月份挂钩,月份逐渐成为划分四季的唯一标准,而周历的岁首所在月份并未固定下来,这导致季节随岁首的变化而发生推移。尤其是到了春秋后期,周历以建子之月为岁首,四季已不再能够反映天时,它所起的作用仅限于将一年十二个月平均划分为四段。在季节不合于天时的弊端日益显露之时,孔子从杞国求得"夏时",并认识到了它的优越性。此后,孔子不竭余力地呼吁"行夏之时",成为早期四时制向后世成熟四时制过渡的契机。战国中后期,各诸侯国普遍改用夏时,早期四时制逐渐为成熟四时制所替代,季节的物候意义失而复得。

回眸历史 翰墨弥珍——《民国名人手迹》读后

《礼记·礼运》篇云:“孔子曰:我欲观夏道,是故之杞而不足微也,吾得《夏时》焉;吾欲观股道,是故之宋而不足微也,吾得《坤乾》焉。《坤乾》之义,《夏时》之等,吾以是观也。”此处所说的《夏时》即《大戴礼》中的《夏小正》;《坤乾》,是殷《易》、《归藏》,都是夏殷两代的重要史料。孔子研究夏殷史实,尽管已得了《夏时》和《坤乾》,但仍深感不足,这是孔子在修史时的感叹。可见史料文献对研究工作之重要。革命导师马克思在研究工作中也十分重视文献资料.

胡萝卜系列杂交新品种

胡罗卜是营养价值极高的一种世界性蔬菜,在我国的种植面积不断扩大,目前我国已成为世界上种植面积与总产量最高的国家,针对我国胡萝卜市场迅速发展的需要,北京蔬菜研究中心培育出了系列胡萝卜杂交种,现介绍如下.

Long-term precipitation change by hourly data in Haihe River Basin during 1961–2004

Hourly summer precipitation data recorded at 21 stations during 1961-2004 in the Haihe River Basin in North China were an alyzed. The results show that the precipitation frequency and amount and the morning peak mainly relating to longduratiol rainfall events decreased during this period, whereas the normalized afternoon peak mainly relating to short-duration event： increased, which may suggest that the proportion of short-duration rainfall has increased as the total summer rainfall has de creased. For short-duration events, the mean intensity and peak intensity increased at most stations and the time to peak inten sity decreased, which may be attributable to the higher thermal contrast between the warmer lower surface and cooler uppe level. In the case of long-duration events, the total amount was significantly correlated with the East Asian summer monsool index for the period 1961-2001 （correlation coefficient of 0.63）. Although the total amount of rainfall in long-duration event： decreased in the basin, the mean intensity and peak intensity, as well as the extreme hourly precipitation, increased in the western basin and decreased in the eastern basin.

The projected temporal evolution in the interannual variability of East Asian summer rainfall by CMIP3 coupled models

The projected temporal evolution in the interannual variability of East Asian summer rainfall in the 21st century is investigated here,by analyzing the simulated results of 18 coupled models under the 20th century climate experiment and scenario A1B.The multi-model ensemble(MME)mean projects two prominent changes in the interannual variability of East Asian summer rainfall in the 21st century under scenario A1B.The first change occurs around the 2030s,with a small change before and a large increase afterward.The intensity of the interannual variability increases up to approximately 0.53 mm/d in the 2070s,representing an increase of approximately 30% relative to the early 21st century.The second change happens around the 2070s,with a decrease afterward.By the end of the 21st century,the increase is approximately 12% relative to the early 21st century.The interannual variability of two circulation factors,the western North Pacific subtropical high(WNPSH)and the East Asian upper-tropospheric jet(EAJ),are also projected to exhibit two prominent changes around the 2030s and 2070 under scenario A1B,with consistent increases and decreases afterward,respectively.The MME result also projects two prominent changes in the interannual variability of water vapor transported to East Asia at 850 hPa,which occurs separately around the 2040s and 2070s,with a persistent increase and decrease afterward.Meanwhile,the precipitable water interannual variability over East Asia and the western North Pacific is projected to exhibit two prominent enhancements around the 2030s and 2060s and an increase from 0.1 kg/m2 in the early 21st century to 0.5 kg/m2 at the end of the 21st century,implying a continuous intensification in the interannual variability of the potential precipitation.Otherwise,the intensities of the three factors'(except EAJ)interannual variability are all projected to be stronger at the end of the 21st century than that in the early period.These studies indicate that the change of interannual variability of the East Asian summer rainfall is caused by the variability of both the dynamic and thermodynamic variables under scenario A1B.In the early and middle 21st century,both factors lead to an intensified interannual variability of rainfall,whereas the dynamic factors weaken the interannual variability,and the thermodynamic factor intensifies the interannual variability in the late period.

The zonal propagating characteristics of low-frequency oscillation over the Eurasian mid-high latitude in boreal summer

Using 32-yr National Centers for Environment Prediction-National Center for Atmospheric Research(NCEP-NCAR) reanalysis data,we investigated zonal propagation and circulation characteristics of the low-frequency circulation for the prevailing period over Eurasian mid-high latitude in boreal summer(May-August) in terms of empirical orthogonal function(EOF),linear regression,and phase analysis and so on.We found that the dominant periods of the low-frequency circulation are 10-30 days and it clearly shows meridional(southward) and zonal(westward) propagation features at the middle troposphere(500 hPa).The average zonal speed of the 10-30 days low-frequency oscillation(LFO) is about 9-10 longitudes per day.Further analysis shows that the southernmost part of the polar vortex in the northern hemisphere exhibits westward clockwise rotation in the eastern hemisphere in boreal summer.Also,the southernmost tips of 5400 and 5500 gpm contours,which indicate the site of the major trough in the eastern hemisphere,obviously move westwards.The southernmost tip of 5500 gpm contour line propagates westwards at the speed of about 9-10 longitudes per day,which is consistent with the mean zonal speed of the westward propagation of the low-frequency circulation.Moreover,the 10-30-day LFO-related cold air also shows west propagation feature with respect to LFO phases.The westward propagation of the LFO is the low-frequency-scale embodiment of the clockwise rotation of polar vortex.The cold air activities closely related to polar vortex or to ridge-trough system activities is the essential circulation of 10-30 days LFO circulation over the Eurasian mid-high latitude in boreal summer.