Simulation of the Radiative Effect of Black Carbon Aerosols and the Regional Climate Responses over China

As part of the development work of the Chinese new regional climate model (RIEMS), the radiative process of black carbon (BC) aerosols has been introduced into the original radiative procedures of RIEMS, and the transport model of BC aerosols has also been established and combined with the RIEMS model. Using the new model system, the distribution of black carbon aerosols and their radiative effect over the China region are investigated. The influences of BC aerosole on the atmospheric radiative transfer and on the air temperature, land surface temperature, and total rainfall are analyzed. It is found that BC aerosols induce a positive radiative forcing at the top of the atmosphere (TOA), which is dominated by shortwave radiative forcing. The maximum radiative forcing occurs in North China in July and in South China in April. At the same time, negative radiative forcing is observed on the surface. Based on the radiative forcing comparison between clear sky and cloudy sky, it is found that cloud can enforce the TOA positive radiative forcing and decrease the negative surface radiative forcing. The responses of the climate system in July to the radiative forcing due to BC aerosols are the decrease in the air temperature in the middle and lower reaches of the Changjiang River and Huaihe area and most areas of South China, and the weak increase or decrease in air temperature over North China. The total rainfall in the middle and lower reaches of the Changjiang River area is increased, but it decreased in North China in July.

On board measurement of black carbon aerosols over the Arctic Ocean in summer

This paper presents aerosol black carbon （BC） concentrations measured at deck level on board the R/V XUE LONG icebreaker. The vessel cruised the Arctic Ocean carrying an in situ aethalometer during the summers of 2008 and 2010. The courses of the third Chinese National Arctic Research Expedition （3rd CHINARE- Arctic, August 2008） and fourth Chinese National Arctic Research Expedition （4th CHINARE-Aretic, from late July to August 2010） were bounded by 173°W-143°W and 178°E-150°W, with northernmost points 85°25′N and 88°26′N, respectively. Results show low surface BC concentrations over the ocean throughout the courses, with means （standard error） of 6.0 （：t_4.7） ng.m-a for 3rd CHINARE-Arctic, and 8.4（±7.1） ng.m^-3 for 4th CHINARE- Arctic. It is clear that these onboard BC concentrations are similar to reported data from coastal stations in the Arctic region. The latitude-average BC concentration varied from 3.0-26.2 ng.m-3 for 3rd CHINARE-Arctic, to 4.2-20.5 ng-m-a for 4th CHINARE-Arctic. At latitudes higher than 72°N for 3rd CHINARE-Arctic and 75°N for 4th CHINARE-Arctic, BC concentrations were lower and had negligible latitudinal gradients. Analysis indicates that the presence of the Arctic front isolates the lower atmosphere of the high-latitude Arctic Ocean from low-latitude terrestrial transport. This maintains the very low BC concentrations and negligible concentration gradients at high latitudes of the Arctic Ocean during summer. Calculated airmass backward trajectories for the two expeditions show that the Arctic front in 2010 was further north than in 2008, which caused different latitudinal variation of BC concentration in the two years.

MORPHOLOGY OF BLACK CARBON AEROSOLS AND UBIQUITY OF 50-NANOMETER BLACK CARBON AEROSOLS IN THE ATMOSPHERE

Different-sized aerosols were collected by an Andersen air sampler to observe the detailed morphology of the black carbon （BC） aerosols which were separated chemically from the other accompanying aerosols, using a Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer （SEM-EDX）. The results indicate that most BC aerosols are spherical particles of about 50 nm in diameter and with a homogeneous surface. Results also show that these particles aggregate with other aerosols or with themselves to form larger agglomerates in the micrometer range. The shape of these 50-nm BC spherical particles was found to be very similar to that of BC particles released from petroleum-powered vehicular internal combustion engines. These spherical BC particles were shown to be different from the previously reported fullerenes found using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry （MALDI-TOF-MS）.

Observation of black carbon aerosol in Beijing, 2003

The objective of this study was to determine the black carbon concentration in Beijing in 2003.The aerosol properties were measured using an Aethalometer and a tapered element oscillating microbalance(TEOM)on the roof of the Physics Building of Peking University(39.99°N,116.31°E)from July to August 2003 and from November 2003 to January 2004.The average black carbon(BC)concentrations in the summer and winter were 8.80 and 11.4μg/m3,respectively.During winter,two different cyclone cut offs were installed at the inlet of an aethalometer.The BC mass concentration in TSP,PM_(10),and PM_(2.5)were obtained.The results indicated that in winter aerosol,90%of BC exited in PM_(10)and 82.6%of BC exited in PM_(2.5).The BC in PM_(10)accounted for 5.11%of the PM_(10)mass.

Characteristics and source of black carbon aerosol over Taklimakan Desert

Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter】spring】autumn】summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,which was just the reverse of that in the urban area.The contribution of BC to the total mass of PM10 on non-dust storm days was～11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,and the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.

Characterization of Black Carbon in the Ambient Air of Agra,India:Seasonal Variation and Meteorological Influence

This study characterizes the black carbon in Agra, India home to the Taj Mahal--and situated in the lndo-Gangetic basin. The mean black carbon concentration is 9.5 μg m-3 and, owing to excessive biomass/fossil fuel combustion and automobile emissions, the concentration varies considerably. Seasonally, the black carbon mass concentration is highest in winter, probably due to the increased fossil fuel consumption for heating and cooking, apart from a low boundary layer. The nocturnal peak rises prominently in winter, when the use of domestic heating is excessive. Meanwhile, the concentration is lowest during the monsoon season because of the turbulent atmospheric conditions and the process of washout by precipitation. The ratio of black carbon to brown carbon is less than unity during the entire study period, except in winter （December）. This may be because that biomass combustion and diesel exhaust are major black carbon contributors in this region, while a higher ratio in winter may be due to the increased consumption of fossil fuel and wood for heating purposes. ANOVA reveals significant monthly variation in the concentration of black carbon; plus, it is negatively correlated with wind speed and temperature. A high black carbon mass concentration is observed at moderate （1-2 m s-1） wind speed, as compared to calm or turbulent atmospheric conditions.

Modeled Influence of East Asian Black Carbon on Inter-Decadal Shifts in East China Summer Rainfall

Two inter-decadal shifts in East China summer rainfall during the last three decades of the 20th century have been identified.One shift occurred in the late 1970s and featured more rainfall in the Yangtze River valley and prolonged drought in North China.The other shift occurred in the early 1990s and featured increased rainfall in South China.The role of black carbon(BC) aerosol in the first shift event is controversial,and it has not been documented for the second event.In this study,the authors used Geophysical Fluid Dynamics Laboratory's(GFDL's) atmospheric general circulation model known as Atmosphere and Land Model(AM2.1) ,which has been shown to capture East Asian climate variability well,to investigate these issues by conducting sensitive experiments with or without historical BC in East Asia. The results suggest that the model reproduces the first shift well,including intensified rainfall in the Yangtze River and weakened monsoonal circulation.However,the model captures only a fraction of the observed variations for the second shift event.Thus,the role of BC in modulating the two shift events is different,and its impact is relatively less important for the early 1990s event.

Black Carbon Particles in the Urban Atmosphere in Beijing

A study of the concentration of black carbon particles and its variation in the urban atmosphere has been carried out since 1996 in the Beijing area. The measurements were done in the late autumn and early winter each year, the period before and after domestic heating activities begin. The results show the presence of black carbon particles at the high level that vary over a large range in the urban atmosphere in Beijing. The mean value of daily average concentration for the whole observation period of 1996-2004 is 20.0 μgm^-3. An evident decrease of black carbon particle concentration in the Beijing area is observed after 2000, and the daily average concentration of black carbon particles is estimated to be 16.0 μgm^-3 with a variation range of 2.10-50.50 μgm^-3 for the period of 2000-2004. The observation method and main variation behavior characteristics of black carbon particles in the urban atmosphere in the Beijing area are given and discussed.

A Modeling Study of the Climate Effects of Sulfate and Carbonaceous Aerosols over China

In this paper, the RIEMS 2.0 model is used to simulate the distribution of sulfate, black carbon, and organic carbon aerosols over China （16.2°-44.1°N, 93.4°-132.4°E） in 1998. The climate effects of these three anthropogenic aerosols are also simulated. The results are summarized as follows： （1） The regional average column burdens of sulfate, BC, OC, and SOC were 5.9, 0.24, 2.4, and 0.49 mg m-2, with maxima of 33.9, 1.48, 7.3, and 1.1 mg m-2, respectively. The column burden and surface concentration of secondary organic carbon accounted for about 20% and 7%, respectively, of the total organic carbon in eastern China. （2） The radiative forcings of sulfate, organic carbon, and black carbon at the top of the atmosphere were -1.24, -0.6, and 0.16 W m 2 respectively, with extremes of -5.25, -2.6, and 0.91 W m-2. （3） The surface air temperature changes caused by sulfate, organic carbon, and black carbon were -0.07, -0.04, and 0.01 K, respectively. The air temperature increase caused by black carbon at 850 hPa was higher than that at the surface. The net effect of the three kinds of anthropogenic aerosols together decreased the annual average temperature by -0.075 K; the maximum value was -0.3 K. （4） Black carbon can reduce the precipitation in arid and semi-arid areas of northern China and increase the precipitation in wet and semi-wet areas of southern China. The average precipitation increase caused by black carbon in China was 0.003 mm d^-1. The net effect of the three kinds of anthropogenic aerosols was to decrease the precipitation over China by 0.008 mmd ^-1.

Characteristics of Anthropogenic Sulfate and Carbonaceous Aerosols over East Asia: Regional Modeling and Observation

The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with the limited aerosol observations over the region. The aerosol module consists of SO2, SO4^2-, hydrophobic and hydrophilic black carbon （BC） and organic carbon compounds （OC）, including emission, advections, dry and wet deposition, and chemical production and conversion. The simulated patterns of SO2 are closely tied to its emission rate, with sharp gradients between the highly polluted regions and more rural areas. Chemical conversion （especially in the aqueous phase） and dry deposition remove 60% and 30% of the total SO2 emission, respectively. The SO4^2- shows less horizontal gradient and seasonality than SO2, with wet deposition （60%） and export （27%） being two major sinks. Carbonaceous aerosols are spatially smoother than sulfur species. The aging process transforms more than 80% of hydrophobic BC and OC to hydrophilic components, which are removed by wet deposition （60%） and export （30%）. The simulated spatial and seasonal SO4^2-, BC and OC aerosol concentrations and total aerosol optical depth are generally consistent with the observations in rural areas over East Asia, with lower bias in simulated OC aerosols, likely due to the underestimation of anthropogenic OC emissions and missing treatment of secondary organic carbon. The results suggest that our model is a useful tool for characterizing the anthropogenic aerosol cycle and for assessing its potential climatic and environmental effects in future studies.

Measurement of Atmospheric Black Carbon Concentration in Rural and Urban Environments: Cases of Lamto and Abidjan

Black carbon is one of the primary aerosols directly emitted from biomass known to have strong absorbing properties. The INDAAF and PASMU observational field campaigns which took place (2018) in Abidjan (urban area) and Lamto (rural area) allow the analysis of Black carbon concentration at different time scales through real-time measurements using an analyzer named Aethalometer AE-33. Results presented here show at Lamto: 1) for the diurnal scale an average of 1.71 ± 0.3 μg⋅m-3 (0.34 ± 0.09 μg⋅m-3) in the dry (wet) season;2) for the monthly scale an average of 1.14 ± 0.84 μg⋅m-3;3) on the seasonal scale, an average of 2.2 ± 0.02 μg⋅m-3 (0.6 ± 0.19 μg⋅m-3) in the dry (wet) season. The black carbon variation at Lamto is seasonal with an amplification factor of 85.6. Regarding the urban area of Abidjan, due to sampling issues, our analyses were limited to daily, diurnal and weekly time scales. We observed: a) at a daily scale an average of 5.31.± 2.5 μg⋅m-3, b) diurnal scale, an average ranging from 6.87 to 13.92 μg⋅m-3. The analysis indicated that emissions from urban areas are more related to social and economic activities, with weekday concentrations (7.24 μg⋅m-3) higher than concentrations over the weekend (e.g. Saturday 6.59 μg⋅m-3 and Sunday 6.00 μg⋅m-3). Moreover, BC concentration in Abidjan is quite noticeable compared to that of rural areas (Lamto). The ratio between the maximum values of the two areas is of the order of 5.86. In addition, concentrations in some urban areas are slightly above the daily threshold set by the WHO (10 μg⋅m-3). Therefore, the levels of urban BC concentrations are alarming whilst rural BC concentrations remain below daily WHO thresholds and are of the same magnitude as those of West African megacities. This study underlies that BC concentrations at Lamto are mainly related to biomass combustion sources while those from urban areas are related to traffic sources. The latter is permanently active, unlike those in rural Lamto, which is seasonal.

内蒙古典型草原2010~2021年黑碳气溶胶浓度变化及影响因素分析

分析了2010~2021年内蒙古锡林浩特国家气候观象台大气成分观测站黑碳气溶胶浓度观测数据,阐明了黑碳气溶胶浓度时间变化规律,并初步讨论了其与气象要素的关系,以期为大气黑碳气溶胶污染防治工作提供科学依据.结果表明:不同季节、不同风速下,几乎均在南偏西风向时黑碳气溶胶浓度增大且最高,而在东北风向时其浓度几乎不变甚至略减少且最低;黑碳气溶胶浓度日变化整体呈现出明显的四季均为“单峰型”变化特征,冬季峰值出现时间较其他三个季节晚,四季谷值出现时间一致;季节变化总体上呈现出浓度及其标准差均为秋冬季高于春夏季的特征,说明观测点黑碳气溶胶浓度在高值期间的秋冬季,其变化幅度也较大;由于能源结构的改变及节能减排措施的成效,近10年观测点黑碳气溶胶浓度呈明显下降趋势,其变化与气温、降水呈极显著负相关,与相对湿度呈极显著正相关.

THE DIRECT EFFECTS OF AEROSOLS AND DECADAL VARIATION OF GLOBAL SEA SURFACE TEMPERATURE ON THE EAST ASIAN SUMMER PRECIPITATION IN CAM3.0

Using the CAM3.0 model, we investigated the respective effects of aerosol concentration increasing and decadal variation of global sea surface temperature(SST) around year 1976/77 on the East Asian precipitation in boreal summer. By doubling the concentration of the sulfate aerosol and black carbon aerosol separately and synchronously in East Asia(100-150 °E, 20-50 °N), the climate effects of these aerosols are specifically investigated. The results show that both the decadal SST changing and aerosol concentration increasing could lead to rainfall decreasing in the center of East Asia, but increasing in the regions along southeast coast areas of China. However, the different patterns of rainfall over ocean and lower wind field over Asian continent between aerosol experiments and SST experiments in CAM3.0 indicate the presence of different mechanisms. In the increased aerosol concentration experiments, scattering effect is the main climate effect for both sulfate and black carbon aerosols in the Eastern Asian summer. Especially in the increased sulfate aerosol concentration experiment, the climate scattering effect of aerosol leads to the most significant temperature decreasing, sinking convection anomalies and decreased rainfall in the troposphere over the central part of East Asia. However, in an increased black carbon aerosol concentration experiment, weakened sinking convection anomalies exist at the southerly position. This weakened sinking and its compensating rising convection anomalies in the south lead to the heavy rainfall over southeast coast areas of China. When concentrations of both sulfate and black carbon aerosols increase synchronously, the anomalous rainfall distribution is somewhat like that in the increased black carbon concentration aerosol experiment but with less intensity.

霾过程黑碳对气溶胶散射吸湿增长的影响

利用成都市2017年10~12月逐时的“干”气溶胶散射系数、吸收系数和环境气象监测资料,结合同时次气溶胶粒径吸湿增长因子(Gf)的反演数据,分析了4类霾强度条件下黑碳浓度(C_(BC))的变化特征,并基于广义可加模型(GAM)探讨了C_(BC)对气溶胶散射吸湿增长因子(f)的影响机制.结果表明:(1)轻微、轻度、中度和重度霾强度条件下的C_(BC)均服从对数正态分布,其均值随霾强度的增加而增大,变差系数则随霾强度的增加而减小.(2) C_(BC)与Gf之间呈现非线性负相关,C_(BC)与C_(PM2.5/PM10)(细颗粒物质量浓度与粗颗粒物质量浓度之比)之间则呈现非线性正相关(均通过了α=0.01的显著性检验);随着霾的渐近演化,Gf随C_(BC)增加而减小的趋势持续增强,C_(PM2.5/PM10)随C_(BC)增加而增大的趋势则持续减弱.(3) Gf与C_(PM2.5/PM10)之间存在显著的交互作用(通过了α=0.001的显著性检验),以Gf与C_(PM 2.5/PM10)为双变量的GAM模型能更好地表征f的变化特征.

2021年苏州黑碳气溶胶浓度特征及来源解析

于2020年12月1日—2021年11月30日利用7波段黑碳仪(AE-31)观测苏州地区黑碳(BC)浓度变化特征,并使用黑碳仪模型和后向轨迹模型分析BC排放来源和潜在源区。结果发现,苏州地区BC年平均质量浓度为(1.29±0.64)μg/m^(3),冬季BC质量浓度最高,为(1.61±0.89)μg/m^(3),秋季为(1.34±0.61)μg/m^(3),春季为(1.23±0.48)μg/m^(3),夏季最低,为(1.03±0.43)μg/m^(3)。各季节工作日、非工作日BC质量浓度日变化均呈早晚双峰分布规律。BC质量浓度与风速、气温、降水量呈负相关,与相对湿度相关性并不显著。黑碳来源解析结果表明,相比于固体燃料(如煤和生物质燃烧),液体燃料(如交通排放)对苏州BC质量浓度的贡献在各季节均占主要地位(74.2%~76.3%),且夏季最高,冬季最低。同时,后向轨迹模拟和浓度轨迹权重分析的潜在源区结果显示,与本地污染相比,影响苏州地区BC的更多为输送型气团;各季节BC的潜在源区也稍有差异,主要以西南方向的影响为主。

AE-31型黑炭监测仪及其使用维护与故障处理

本文介绍了黑炭气溶胶的基础知识和大气成分观测常用的黑炭气溶胶监测仪Aethalometer AE-31型的工作原理、构成部件、使用要点、巡查维护和故障排查处理等内容。对日常工作中常用的维护使用经验进行分析总结,给出简单故障的排查处理方法,以提高黑炭气溶胶监测仪运行的稳定性以及数据的完整性和准确性。

Spatial Variability and Radiative Impact of Aerosol along the Brahmaputra River Valley in India: Results from a Campaign

The first ever land campaign to study the spatial variability of the aerosol characteristics along the Brahmaputra river valley (BRV) in Assam, North-Eastern India, was conducted during 2011. Measurements were made over 13 locations for Aerosol Optical Depth (AOD), scattering coefficient, particulate matter, black carbon (BC) concentration and meteorological parameters. The BRV is divided into three sectors longitudinally viz western sector (WS), central sector (CS), and eastern sector (ES). Significant Spatial heterogeneity in AOD and BC concentration was observed (p < 0.05) with the highest values over WS and a continual decrease from WS to ES with aerosol dominance in PM2.5 category along the entire valley. The Angstrom coefficient measured using different wavelength pairs showed spatial variability indicating dominance of fine particles over WS and coarse particles in ES with a probable bimodal distribution. The scattering and absorption coefficient shows dominance of both types of aerosol over WS than other areas. The shortwave radiative forcing was higher over the WS than CS and ES of the valley. The campaign revealed that under favorable wind conditions, the BRV is loaded with significant amount of natural and anthropogenic aerosol during local winter and is influenced by the long-range transport of aerosols from the Indo-Gangetic plain.

Aerosol Properties over Ranchi Measured from Aethalometer

Continuous and near-real-time measurements of the mass concentration of Aerosol Black Carbon (BC) were carried out 1st to 31st July 2010 of rainy season and compare with data of July-2010 to March-2011 using an Aethalometer (model AE-31 of Magee Scientific, USA). The principle of the Aethalometer is to measure the attenuation of a beam of light transmitted through a filter, while the filter is continuously collecting an aero-sol sample. This measurement is made at successive regular intervals of a time base period has been. the BC mass concentration is estimated by measuring the change in the transmittance of a quartz filter tape, on to which the particles impinge. The instrument was operated at a time base of 5 min, round the clock with a flow rate of 4-liter min–1, to study the impact of rainy season on black carbon concentrations over a typical urban environment namely Ranchi, India. BC concentrations were high during morning (0600 to 0900 h) and evening hours (1900 to 2300 h) compared to afternoon hours. During early morning hours, high values of BC are attributed to the turbulence set-in by the solar heating which breaks the night-time stable layer and aero-sols in the nocturnal residual layer are mixed up with those near the surface.

中国内地和印度黑碳气溶胶对东亚冬季气候的影响研究

黑碳(BC)气溶胶(简称黑碳)对区域和全球气候变化具有重要影响。为了进一步认识亚洲地区黑碳的区域气候效应,本文使用新一代的区域气候—化学模式RegCM4,研究了来自印度和中国内地的黑碳排放对东亚冬季气候的影响。结果表明:来自中国内地和印度的黑碳排放可导致东亚地区黑碳的区域平均柱含量、大气顶和地表有效辐射强迫分别变化了+1.78 mg m^(−2)、+1.98 W m^(−2)和−2.17 W m^(−2)。中国内地和印度黑碳对东亚气候的影响机制相同。印度黑碳对东亚冬季气候的影响主要通过对大气动力过程的调整来实现,由此造成的散射气溶胶浓度增加可导致该区域850 hPa附近和地表气温降低,而中国内地的黑碳还可直接影响东亚气候,其加热效应可导致该区域大部分地区850 hPa附近的气层变暖。由于中国内地黑碳在东亚地区占主导,其在影响东亚区域气候变化方面发挥着更重要的作用。总体而言,两地总的黑碳会造成850 hPa高度附近云量减少和气温升高;地表日照时数减少,气温、感热通量和地表蒸发量下降;边界层高度降低和散射气溶胶的柱含量上升。研究结果还进一步反映了东亚冬季气候对不同排放黑碳的响应表现出了一定的非线性。

中国东西部典型本底站黑碳气溶胶时空分布及来源分析

基于2007-2018年4个代表性大气本底站(临安、上甸子、龙凤山和瓦里关)的逐小时黑碳(black carbon,BC)观测数据和同期气象资料,开展中国东西部BC时空变化特征分析;利用黑碳仪模型和浓度权重轨迹(concentration weighted trajectory,CWT)分析法对比分析了各站点BC的来源类型和潜在源区。结果表明:(1)中国BC质量浓度分布呈现“东高西低”的特点,各站点BC多年平均质量浓度依次为临安站[(3553±2336)ng·m^(-3)]、上甸子站[(2045±1918)ng·m^(-3)]、龙凤山站[(1966±2104)ng·m^(-3)]、瓦里关站[(455±380)ng·m^(-3)]。(2)东西部4个典型本底站点BC质量浓度季节变化和日变化特征不同。东部站点为冬季最高、春秋季次之、夏季最低,而西部站点表现为春季最高、夏季次之、冬季再次之、秋季最低;东部站点BC质量浓度日变化以“双峰型”分布为主,西部瓦里关站呈“昼高夜低”的高山站特征。研究期内,各站BC呈逐年显著下降的趋势,体现了中国大气污染治理的成效。(3)BC主要来自液态燃料的燃烧(简记为“BC liquid”);受冬季采暖影响,夏季BC liquid大于冬季。(4)受亚洲季风影响,不同季节近地面风场对东西部站点BC质量浓度的影响不同,BC潜在来源也不同。东部站冬季潜在源区多在周边大城市群,高值区范围较大;夏季多来自各站偏南方向。西部瓦里关站夏季潜在源区为四川北部城市群,冬季为中国兰州附近和印度北部。