环境制图中数量特征的表示方法研究

对环境制图中反映数量特征的定点符号法,包括几种连续和分级比率符号、非比率分级符号以及相关内容数量特征的表示进行了具体分析比较.对表示要素数量特征面状分布的网格法和等值线法,也结合实例进行了评述.     

基于层次分析法的黄河上游水源涵养区生态系统恢复力评价——以甘南州、临夏州为例北大核心CSCD

在全球气候变化背景下,人类活动对生态环境质量影响的定量评价是区域生态保护与高质量发展的关键问题。本文基于层次分析法(AHP)和GIS可视化空间分析技术,应用遥感反演的生态系统分类资料和社会经济统计资料等,构建了包含社会经济、土地压力、自然条件3个准则层的生态系统恢复力评价指标体系,结合指标时空尺度无量纲化与综合指数法,进行了甘肃省甘南州、临夏州2000—2020年的生态系统恢复力定量评估。结果表明:研究区域空间尺度生态恢复力范围分别为0.14—0.65(2000年)、0.12—0.72(2005年)、0.07—0.70(2010年)、0.12—0.70(2015年)、0.28—0.82(2020年);甘南生态系统恢复力较高,临夏生态系统恢复力较低,在空间分布上,生态系统恢复力呈现北低南高的总体特征,高生态恢复力的乡镇以草地、森林、灌木生态系统为主,低生态恢复力的乡镇以农田、城镇生态系统为主;在时序变化特征中,生态系统恢复力总体向好,呈现先上升、后下降、最后上升趋势,受人类活动与气候变化共同作用。     

一种基于灰度块匹配的视野监测算法

针对视野移动方向的判断问题,该文介绍了运动补偿的常用方法及应用,提出了基于灰度块匹配的视野移动监测算法。通过对比各种算法计算复杂度和计算时间,发现灰度投影算法准确率低、计算量较小;块匹配搜索算法中的穷尽搜索算法准确率高,但是计算量较大。为了发挥以上两者算法的优势,将两者结合形成了灰度块匹配算法,并通过实验证实了灰度块匹配算法在实时监测系统中的可行性。     

驼背鲈引种驯养及人工诱导性腺发育和繁殖

为探讨通过人工诱导获得驼背鲈成熟亲鱼的途径,在室内水池进行驼背鲈驯养研究;用口服和注射性激素、控温、控光、营养强化、模拟生态条件等方法处理驼背鲈以诱导其性腺发育。结果表明,控光和模拟生态条件不能有效诱导性腺发育;激素、控温和营养强化相结合可诱导驼背鲈性腺发育并成熟。对其中１ 组诱导成熟的亲鱼（雌、雄各１ 尾）进行人工催产后,亲鱼自然产卵受精,孵出仔鱼２ 万尾。驼背鲈在驯养条件下生长较快;通过人工控制和诱导可达到性腺发育和成熟,性腺发育速度较快。     

苏北潮滩湿地不同生态带碳、氮、磷分布特征*

通过对比苏北潮滩湿地不同生态带的表层以及柱状沉积物中总有机碳、总氮、总磷和有机磷含量,并结合不同植被不同植株部位中碳、氮、磷的含量变化,分析了潮滩沉积物中碳、氮、磷的垂向和水平分布特征与规律,探讨了不同生态带以及潮滩植被对碳、氮、磷等生源要素的富集作用。对比分析结果表明:苏北潮滩湿地各生态带对不同的测量指标有着不同的富集作用,互花米草滩的总有机碳、总氮和有机磷含量要远大于其他几个生态带,光滩沉积物中总磷的含量最高; 粒度效应是控制互花米草前缘地带以及互花米草滩沉积物中有机碳和氮分布的一个重要因素,盐蒿和芦苇滩中有机碳和氮的分布更多的是受粒度之外的其他因素影响; 不同生态带表层沉积物中的C/N比值分布,大致可反映其有机物来源的差异,而不同生态带中柱状沉积物中的C/N比值相对接近,很难根据C/N比值大小来对不同生态带中的有机物来源进行判断,这可能是埋藏在柱状沉积物中的有机物更多的受到了早期成岩作用造成的。植被对潮滩湿地中碳、氮、磷的分布有着重要影响,3种物质在互花米草、盐蒿和芦苇中的含量差别不是很大,因此潮滩植被对沉积物中上述3种物质的贡献差别主要是由不同植被的生物量和其所处环境的沉积动力差异造成的。     

Investigation of the SA evolution by using the CHAOS-4 model over 1997–2013

The temporal and spatial evolution characteristics of the geomagnetic secular acceleration(SA) are investigated, based on CHAOS-4 core field model during the period of 1997–2013. The SA evolution on a short time scale is associated with the phenomenon of the geomagnetic jerk. More details of the global extent and the occurrence time of the successive jerks(the 1999, 2003, 2007, and 2011 jerks) are obtained. The location, size and reversed polarity pattern for the 1999 jerk are similar to those for the 2003 jerk in the Asian-Indian sector. While the 2007 and 2011 jerks mainly take place in the Atlantic sector. The direction and speed of the shift for the four jerks are different, identified by the occurrence time of the jerks. The zonal motions of the SA patches exhibit an oscillation pattern in the Asian-Indian sector, whereas a purely westward drifting pattern is along the equator in the Atlantic sector. It is believed that the shift of the jerks is related to the motion of SA-B_r patches observed at the core-mantle boundary(CMB).     

海带的一个自然突变型

在多细胞藻的遗传学研究中,被发现的突变型很少[1].绿藻中有一些突变型,其中较多的是某种石莼(Ulva mutabilis)[2].三浦昭雄等在紫菜中发现突变型.在褐藻中未见有突变型的报道.这里所报道的是海带(Laminaria japonica)的一个突变型.     

Semi-analytical solutions for vertically and laterally loaded piles in multilayered soil deposits

In geotechnical practice, it is of considerable importance to assess the behavior of vertical–lateral coupled loading piles in multilayered soil deposits. This study deals with a semi-analytical formulation for the performance of a pile suffering from combined vertical and lateral loads. The emphasis is on quantifying the mobilization of the subgrade reaction provided by the layered soil stratums. In the proposed method, subgrade reactions, correlated with both the accumulative axial load transfer and side resistances depending upon the pile–soil interaction, are abstracted as a series of nonlinear springs in both vertical and lateral directions. On account of this, an alternative transfer matrix method is applied to characterize the pile reaction along the depth under the identified boundary conditions atop the pile; meanwhile, the condition of static equilibrium, between two specific pile segments located at the border of soil layers, is also essential. On this basis, validation of the solution is conducted by comparing with observations from experiments and predictions obtained from other existing methods. In addition, the influence of properties in shallow soil layer and the vertical load on the lateral response of the pile is also discussed. The results indicate a reduction in the lateral displacement and the maximum bending moment within the pile with the increase in the shallow soil stiffness, but a growth with the increase in vertical load due to the “P-Δ effect.”     

Cases-97: Late-Morning Warming And Moistening Of The Convective Boundary Layer Over The Walnut River Watershed

Aircraft, radiosonde, surface-flux, and boundary-layer windprofiler data from the Cooperative Atmosphere Surface Exchange Study's 1997 field project, CASES-97, are combined with synoptic data to study the evolution of the vertically-averaged mixed-layerpotential temperature []and mixing-ratio [Q] onthree nearly-cloudless days from 1000 CST to 1200CST (local noon is approximately 1230 CST). This was achieved through examination of the terms in the time-tendency (`budget')equations for []and [Q]. We estimate three of the terms –local time rate of change, vertical flux divergence, andhorizontal advection. For the [Q]-budget, vertical flux divergence usually dominates, buthorizontal advection is significant on one of the three days. The [Q]-budget balances for two of the three days to within the large experimental error. For the -budget,vertical flux divergence accounts for most of the morningwarming, with horizontal advection of secondary importance.The residual in the -budget has the same sign for all three days, indicating that not all the heating is accounted for. We can balance the []-budgets to within experimental error on two of the three days by correcting the vertical-flux divergence for apparent low biases in the flux measurements of one of the aircraft and in the surface fluxes, and accounting for direct heating of the mixed layer by radiative flux divergence allowing for the effects of carbonaceous aerosols. The [];-budget with these corrections also balances on the third day if horizontal gradients from synoptic maps are used to estimate the horizontal advection. However, the corrected budget for this day does not balance if the horizontal gradient in the advection term is estimated using CASES-97aircraft and radiosondes; we suggest that persistent mesoscale circulations led to an overestimate of the horizontal gradient andhence horizontal advection.     

A grid-based tropospheric product for China using a GNSS network

Tropospheric delay accounts for one source of error in global navigation satellite systems (GNSS). To better characterize the tropospheric delays in the temporal and spatial domain and facilitate the safety-critical use of GNSS across China, a method is proposed to generate a grid-based tropospheric product (GTP) using the GNSS network with an empirical tropospheric model, known as IGGtrop. The prototype system generates the GTPs in post-processing and real-time modes and is based on the undifferenced and uncombined precise point positioning (UU-PPP) technique. GTPs are constructed for a grid form (\(2.0{^{\circ }}\times 2.5{^{\circ }}\) latitude–longitude) over China with a time resolution of 5 min. The real-time GTP messages are encoded in a self-defined RTCM3 format and broadcast to users using NTRIP (networked transport of RTCM via internet protocol), which enables efficient and safe transmission to real-time users. Our approach for GTP generation consists of three sequential steps. In the first step, GNSS-derived zenith tropospheric delays (ZTDs) for a network of GNSS stations are estimated using UU-PPP. In the second step, vertical adjustments for the GNSS-derived ZTDs are applied to address the height differences between the GNSS stations and grid points. The ZTD height corrections are provided by the IGGtrop model. Finally, an inverse distance weighting method is used to interpolate the GNSS-derived ZTDs from the surrounding GNSS stations to the location of the grid point. A total of 210 global positioning system (GPS) stations from the crustal movement observation network of China are used to generate the GTPs in both post-processing and real-time modes. The accuracies of the GTPs are assessed against with ERA-Interim-derived ZTDs and the GPS-derived ZTDs at 12 test GPS stations, respectively. The results show that the post-processing and real-time GTPs can provide the ZTDs with accuracies of 1.4 and 1.8 cm, respectively. We also apply the GTPs in real-time kinematic GPS PPP, and the results show that the convergence time of the PPP solutions is shortened. These results confirm that the GTPs can act as an efficient information source to augment GNSS positioning over China.