2182 Science in China Ser. D Earth Sciences 2005 Vol.48 No.12 2182—2193

Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River

ZHENG Jingyun, HAO Zhixin & GE Quansheng

Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101, China Correspondence should be addressed to Zheng Jingyun (email: [email protected])

Received September 8, 2003; revised May 9, 2004 Abstract The precipitation at 17 stations over the middle and lower reaches of the Yellow River is reconstructed during the period of 1736―1910, using the snow and rainfall records in the Qing Dynasty, together with the instrumental observation data of precipitation and farmland soil moisture content. The soil physics model related to rainfall infiltration and the surface water bal- ance equation are taken as main reconstruction methodology. The field infiltration experiment by artificial rainfall is conducted to check the reliability. And the precipitation series over the middle and lower reaches of the Yellow River and its 4 sub-regions are established, going back to 1736. Analysis of the time series indicates that the abrupt change of precipitation from high to low oc- curs around 1915 over the middle and lower reaches of the Yellow River. During the three peri- ods of 1791―1805, 1816―1830 and 1886―1895, the precipitation is markedly higher than the mean of the series. While both the periods of 1916―1945 and 1981―2000 are characterized by less precipitation. Three periodicities of 22―25a, 3.9a and 2.7a are shown in the precipitation fluctuation over the middle and lower reaches of the Yellow River. Moreover, the periodical signal of 22―25a becomes weaker and weaker since the abrupt change of 1915 and disappears in the late 1940s, and then the periodical signal of 35―40a appears instead.

Keywords: variation, precipitation, last 300 years, the middle and lower reaches of the Yellow River, snow and rain- fall archive in the Qing Dynasty.

DOI: 10.1360/03yd0392

Reconstruction of high-resolution historical climatic to provide long-term high-resolution climatic data[3,4]. series is the key issue for Past Global Changes Since the 1970s, many historical climatic series with (PAGES) and Climate Variability and Predictability index or grade have been established by using Chinese (CLIVAR), the two core projects of the international historical documents, for example, the grade of dry- [5] research programme on global changes. High-resolu- ness/wetness for 120 stations over the last 500 years , [6] tion historical climatic data are vital for our under- and for 45 stations during the past 2000 years . standing the mechanisms of climatic variability, im- However, only a few studies focus on high-resolution [7,8] proving climate model, and distinguishing anthropo- historical precipitation reconstruction . genic effects from the natural forcing on climate Among the Chinese historical documents, the snow change[1,2]. China, with continuous and abundant his- and rainfall archive in the Qing Dynasty is one of the torical documents, is one of the most potential regions most reliable data[9]. This archive covers 268 Fu (Fu is

Copyright by Science in China Press 2005 Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River 2183 an administration between province and the snow depth of each snowfall and the infiltration county) of 18 provinces in the Qing Dynasty from the depth of each rainfall in unit of Fen (1 Fen = 0.32 cm) 32nd year of Kangxi Reign (AD 1693) to the 3rd year or Cun (1 Cun = 3.2 cm), so called “Yu (rainfall) Xue of Xuantong Reign (AD 1911). In which, the records (snowfall) Fen Cun” in Chinese. The latter is syn- since the first year of Qianlong Reign (AD 1736) are thetically assessments of climate for a period, such as continuous and detailed. These records are described the total precipitation for several days, one month, one in two kinds of formats[8]: quantitative data and quali- season or one year (Fig. 1). Compared with other Chi- tative descriptions. The former is the measurement of nese historical documents (e.g. local gazettes), the

Fig. 1. Example for the snow and rainfall records in the Qing Dynasty. (a) Quantitative records about the snow depth; (b) quantitative records about the infiltration depth of each rainfall; (c) qualitative descriptions about synthetically assessments of precipitation for a pe- riod. Only part of the contents is shown in the record. The punctuation is marked by author. The date in bracket is Gregorian calendar.

2184 Science in China Ser. D Earth Sciences snow and rainfall records are usually recorded in high- to understand the characteristics and trends of precipi- resolution and quantitativeness. In the previous works, tation variation in a long-term perspective for effective some case studies have successfully reconstructed utilization of water resource and social-economical precipitation based on this archive[9―12]. In this paper, development in future. the reconstruction and variation of precipitation for the Four sets of data are used in this study. The first is last 300 years over the middle and lower reaches of the snow and rainfall records at 17 stations over the the Yellow River will be discussed. middle and lower reaches of the Yellow River from 1 The study region and data source 1736 to 1911. The second is the instrumental observa- The study region is the middle and lower reaches of tion precipitation data of 17 reconstructed stations and the Yellow River, which belongs to the warm temper- other 5 meteorological stations. The third is the ob- ate and sub-humid climate zone. In this area, precipi- servation data of soil moisture content from 17 agro- tation variation has great impact on agriculture pro- meteorological experimental stations. And the last set duction and social development with obvious seasonal of data is our own investigation data from the field change, great variability, and frequent drought and infiltration experiment at Luancheng (a town near to flood disasters. Recently, the water resource is be- ) Agricultural Ecosystem Experimental coming shorter and shorter under the condition of so- Station from May 30 to June 16, 2002. The name of 17 cial-economical rapid development. There are many stations for precipitation reconstruction, the location of studies focused on historical climate changes in this every agro-meteorological experimental station, and [13,14] area . However, it is very important to reconstruct the period for the observation data used in this study the high-resolution historical precipitation series and are listed in Table 1. Since the instrumental observa-

Table 1 The station name, the location of agro-meteorological experimental station and the period for the observation data used

a) Location of agro-meteorological experimental Period for the instrumental observation Station name station and period for data used precipitation data used Shijiazhuang (Zhengding Fu) Luancheng 1996―2002 1951―2000 Hejian b) (Hejian Fu) Baxian 1990―2000 1930―1937, 1954―2000 1916―2000 (data in 1929, 1938, 1944―1946 (Taiyuan Fu) Jiexiu 1990―2000 and 1948―1949 unavailable) (Jinan Fu) Ji’nan 1990―2000 1916―2000 Yan’an (Yan’an Fu) Yan’an 1990―2000 1951―2000 Xi’an (Xi’an Fu) Xianyang 1990―2000 1923―1926, 1931―2000 Yuncheng (Puzhou Fu and Xie Zhou) Yuncheng 1990―2000 1956―2000 (He’nan Fu) Lushi 1990―2000 1931―1937, 1951―1996 (Kaifeng Fu) Zhengzhou 1981―2000 1930―1938, 1950―2000 Linfen (Pingyang Fu) Linfen 1990―2000 1951―2000 Changzhi (Lu’an Fu) Changzhi 1990―2000 1951―2000 Anyang (Zhangde Fu) Puyang 1990―2000 1919―1926, 1931―1937, 1951―2000 Shangqiu (Guide Fu) Shangqiu 1990―2000 1954―1999 Heze (Caozhou Fu) Heze 1994―2000 1951―2000 Linyi (Yizhou Fu) Linyi 1994―2000 1951―2000 Taian (Tai’an Fu) Taian 1987―2000 1951―2000 Weifang (Qingzhou Fu and Laizhou Fu) Weifang 1994―2000 1951―2000 a) Fu or Zhou bracketed is the place recording the snow and rainfall in the Qing Dynasty corresponding to the station. Fu or Zhou is the administration dis- trict between province and county in the Qing Dynasty. b) The instrumental observation precipitation data of Hejian come from .

Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River 2185 tion precipitation data are not available now, the data River (Weihe for short). The subregion IV includes 5 of Hejian are replaced by that of neighboring station stations of Shangqiu, Heze, Weifang, Tai’an and Linyi, Cangzhou. mainly located in Shandong Province (Shandong for short). 2 Reconstruction of the precipitation 2.1 Sub-region division 2.2 Precipitation reconstruction for individual station during 1736―1910 Difference exists in the annual and inter-annual variation and long-term change trends of precipitation The precipitation for individual station in the period ― variation among 17 stations over the middle and lower 1736 1910 is reconstructed using snow and rainfall reaches of the Yellow River. In order to analyze the records in the Qing Dynasty. The procedure for data precipitation spatial pattern, we divide all of 17 sta- extracting and processing has been detailedly dis- [10,11] tions into 4 sub-regions (Fig. 2) by using the factor cussed in previous studies . In this paper, we in- analysis method based on the precipitation data from troduce the methodology of reconstruction briefly and 1956 to 1996, as well as referring the Chinese climate list pa- rameter value. [15] regionalization . The sub-region I includes 4 stations (i) Precipitation reconstruction. The rainfall equals of Shijiazhuang, Hejian (Cangzhou), Taiyuan and Ji- to the summation of runoff and infiltration approxi- nan, located at the north of the Yellow River ( mately for each rainfall, in terms of the surface water for short). The sub-region II includes 3 stations of balance equation, taking no account of evaporation Anyang, Linfen and Changzhi, located at the south of (because of the high humidity during raining, the tiny Shanxi Province (Jinnan for short). The sub-region III amount of evaporation can be ignored). According to includes 5 stations of Luoyang, Zhengzhou, Yuncheng, the Green-Ampt infiltration model in soil physics, the Xi’an and Yan’an located at the valley of the Weihe infiltration can be given by the equation:

Fig. 2. Sub-region division of precipitation variation over the middle and lower reaches of the Yellow River.

2186 Science in China Ser. D Earth Sciences

F = (θs−θi) × ρ × Zf /ρw, (1) higher evaporation on the ground surface and soil wa- ter decreases rapidly, the soil moisture content for the where θ is the soil saturated moisture content, θ is the s i major part of the studied area is difficult to reach or be initial moisture content, ρ is the apparent specific close to saturate status after raining with light rain and gravity of the soil, ρw is specific gravity of the water, less rainfall in spring. Therefore, the saturated mois- Zf is the depth of infiltration (Yu Fen Cun in the Qing ture content in spring for the most of stations needs to Dynasty). Because the regional soil texture is stable in be adjusted (Table 3). However, for the 5 stations in the studied period, it is reasonable to conclude that the Shandong, spring saturated moisture content need not soil physical parameters, including the apparent spe- to be adjusted because of the relatively high precipita- cific gravity of the soil, saturated moisture content, are tion and frequency. In addition, the initial moisture constant. Therefore, the historical soil physical pa- content calculation method for each layer and grade rameters can be substituted by the observation data was introduced in previous studies[10,11], and the results from agro-meteorological station (Table 2) when cal- are shown in Fig. 3. Limited by the length of paper, culating the infiltration in historical times. Since tem- only one station from each sub-region is selected to be perature increases rapidly with a higher wind speed, taken as examples in Fig. 3 and Table 3.

Table 2 Soil physicl parameters for individual station in the study area −3 −3 Station Layer/cm ρ /g·cm θ 0(%) θ s(%) Station Layer/cm ρ /g·cm θ 0(%) θ s(%) 0―20 1.32 21.0 32.0 0―20 1.46 21.9 31.0 Shijiazhuang Anyang 20―50 1.61 21.0 32.0 20―50 1.49 19.9 30.0 0―20 1.18 22.1 35.0 0―20 1.28 21.0 30.0 Hejian Yan’an 20―50 1.20 27.6 40.0 20―50 1.33 19.0 30.0 0―20 1.31 29.8 35.0 0―20 1.37 20.4 30.0 Taiyuan Xi’an 20―50 1.39 30.0 35.0 20―50 1.52 22.6 31.0 0―20 1.43 21.1 30.0 0―20 1.45 22.4 32.0 Linfen Jinan 20―50 1.45 21.9 30.0 20―50 1.35 23.8 34.0 0―20 1.18 26.9 36.0 0―20 1.37 20.4 29.1 Changzhi Tai’an 20―50 1.37 26.3 36.0 20―50 1.52 22.6 32.3 0―20 1.43 21.9 30.0 0―20 1.34 25.9 37.0 Yuncheng Heze 20―50 1.48 20.3 29.0 20―50 1.56 23.5 33.6 0―20 1.36 22.0 37.0 0―20 1.43 21.0 30.0 Luoyang Linyi 20―50 1.49 21.8 37.0 20―50 1.43 24.0 34.3 0―20 1.32 22.4 30.3 0―20 1.41 20.1 28.7 Zhengzhou Weifang 20―50 1.62 19.9 29.0 20―50 1.45 19.8 28.3 0―20 1.36 22.0 30.0 Shangqiu 20―50 1.32 23.9 31.0

ρ is the apparent specific gravity of the soil, θ0 is the field capacity, θs is the saturated moisture content.

Table 3 Adjusted value of Spring soil saturated moisture content for every grade in representative stations Luoyang Shijiazhuang Linfen Grade 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 March 37% 37% 37% 37% 37% 27% 27% 27% 27% 27% 21% 21% 26% 26% 26% April 30% 30% 30% 37% 37% 27% 27% 27% 27% 27% 21% 21% 26% 26% 26% May 30% 30% 30% 30% 37% 27% 27% 32% 32% 32% 21% 21% 21% 21% 21%

Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River 2187

Fig. 3. Initial moisture content for every grade in layers of 0―20 cm and 20―50 cm for the representative station. In non-rainy season, the rainfall enters the soil en- related to snow depth from 9 stations of Shijiazhuang, tirely, so rainfall equals the infiltration approximately. Taiyuan, Linfen, Yan’an, Xi’an, Jinan, Heze, Anyang But in rainy season (from June to September usually), and Zhengzhou using snow depth and daily precipita- part of rainfall becomes runoff, so the rainfall does not tion records derived from the meteorological observa- enter the soil entirely. Therefore, the rainfall in rainy tion data in January from 1951 to 1990, and correla- season should be given as tion coefficient passed 1% significance level. Sample size and the calculated snow density are listed in Table P= F /β, (2) r 5. Note that because the air temperature is generally where Pr is rainfall; F is the infiltration, which can be lower than 0℃ in January over the middle and lower calculated from eq. (1); β is infiltration coefficient reaches of the Yellow River, and the snow usually listed in Table 4, which can be obtained from the rela- does not melt for one or several days, the relationship tionship of rainfall and intensity in rainy season ac- can be accurately calculated between the depth and cording to approach in ref. [11]. snowfall. Meanwhile, the snow density of station (ii) Snowfall reconstruction. The record format of without data available is replaced by that of its near station. Xue Fen Cun in the Qing Dynasty corresponds to the depth of snowfall in modern meteorological data, so In summary, the monthly, seasonal and annual the Xue Fen Cun can be converted into the snowfall (from March to the next February) precipitation at 17- directly by the conversion equation between snowfall stations during 1736―1910 can be reconstructed by and depth of snow based on modern instrumental ob- calculating each rainfall or snowfall in terms of the servation data. That is above method.

Ps = Hs×ρs/ρw, (3) (iii) Interpolation of missing data. Because the most of snow and rainfall records for 15 years such as 1751 where P is snowfall; H is the depth of snow; ρ is the s s s (accounting for 8.6% in the period 1736―1910) are snow density; ρ is the specific gravity of water. w missing, in order to keep the continuity of the series, The statistical analysis indicates that snowfall well we used the following method to interpolate. The pre-

2188 Science in China Ser. D Earth Sciences

Table 4 The value of infiltration coefficient in representative stations Monthly infiltra- Infiltration Monthly infiltra- Infiltration coef- Monthly infiltra- Infiltration Station Month tion (F)/mm coefficient (β ) tion (F)/mm ficient (β ) tion (F)/mm coefficient (β ) June, September ≤59 1.0 >59 0.84 Shijiazhuang July ≤137 0.72 >137 0.46 August ≤80 0.72 >80 0.46 July ≤110 1.0 110―145 0.84 >145 0.72 Linfen August ≤100 1.0 100―135 0.84 >135 0.72 July ≤130 1.0 130―170 0.84 >170 0.72 Luoyang August ≤120 1.0 120―155 0.84 >155 0.72 September ≤90 1.0 >90 0.84 June, September ≤50 1.0 50―100 0.84 >100 0.72 Linyi July ≤85 0.84 85―145 0.72 >145 0.46 August ≤80 0.84 80―110 0.72 >110 0.46

Table 5 Snow density and correlation coefficients between snowfall and snow depth at some stations Station Taiyuan Shijiazhuang Linfen Anyang Xi’an Yan’an Jinan Zhengzhou Heze Sample size 18 22 21 14 44 30 16 20 9 Coefficient 0.8411 0.8341 0.9084 0.8688 0.7886 0.8937 0.7886 0.8229 0.9048 Snow density/g·cm−3 0.0704 0.0757 0.0790 0.0814 0.0834 0.0838 0.0926 0.0962 0.1204 cipitation in Shijiazhuang, Hejian (Cangzhou), the 5 drought/flood grades of 1 (wet), 2 (above nor- Changzhi and Anyang is interpolated by the drought/ mal), 3 (normal), 4 (below normal) and 5 (dry), which flood grade derived from Natural Disaster Document is the mean value calculated by the distribution prob- of Each Dynasty in the Valley of Haihe River[16]. The ability of 15%, 20%, 30%, 20%, 15%. To be worth precipitation in Jinan, Taian, Heze, Linyi and Weifang noting that this interpolation method may cause larger is interpolated from the seasonal drought/flood indices margin of errors, but the year of missing data with and the equation of precipitation and drought/flood small percentage cannot have clear effect on the re- index[17]. The precipitation in Zhengzhou, Luoyang construction series. and Shangqiu is interpolated by the drought/flood (iv) Reliability validation for the reconstructed se- grade from Drought/flood Chronology in Henan ries. In order to validate the series reliability based on 1) Province . The precipitation in Xi’an and Yan’an is the above method (physical model for short), we also interpolated with the annual drought/flood description develop field experimental method to reconstruct the from Historical Documents on Natural Disaster in precipitation. The field experiment can be described 2) Shaanxi Province . The precipitation in Taiyuan, Lin- with the following procedures: the quantitative rainfall fen and Yuncheng is interpolated by the drought/flood experiment is conducted on a flat farmland by artifi- grade of the Yearly Charts of Dryness/Wetness in cial simulation rainfall device; after raining, we meas- China for the Last 500-Year Period. The interpolation ure the depth of infiltration (located at the boundary of method includes two steps. First, the reconstructed wet and dry soil) and soil physical parameters (without precipitation series are sorted descending. Secondly, seeper on land surface). The experiment designs dif- the precipitation can be calculated corresponding to ferent intensity, duration of rainfall, which mirrors the

1) Hydrological Station of Henan Province, Drought/flood Chronology in Henan Province, 1980, 173―261. 2) Meteorological Observatory of Meteorological Bureau in Shaanxi Province, Historical Documents on Natural Disaster in Shaanxi Province, 1976, 38―145.

Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River 2189 different natural rainfall conditions for different sea- sub-regions precipitation series instead of 17 stations. sons. In which, the rainfall is 6.25 mm, 12.5 mm, 25.0 The reconstruction method is processed as follows: mm, 37.5 mm, 50.0 mm, 60.0 mm, 75.0 mm, 85.0 mm first, the precipitation series (annual mean precipita- and 100.0 mm, representing various natural rainfall tion for all stations in sub-region) of 1951―2000 for types of light rain (0.1―10 mm), moderate rain (10― each sub-region are established, according to the in- 25 mm), heavy rain (25―50 mm) and rainstorm (50― strumental observation data of the precipitation; sec- 100 mm), respectively. The intensity of rainfall is 0.21 ond, spatial representativeness of every sub-region mm·min−1, 0.42 mm·min−1, 0.83 mm·min−1, 1.25 series (precipitation relativity between the region and every individual station) is analyzed, and the regres- mm·min−1 and 1.67 mm·min−1, representing mean sion equation between precipitation of sub-region and rainfall intensity of various types (light rain, moderate individual station is established; finally, the sub- rain, heavy rain, rainstorm and heavy rainstorm). The regional precipitation series is established by the re- initial moisture content is from 24.2% to 78.8% of the gression equation based on individual station instru- field capacity, indicating soil moisture characteristic mental data from 1911 to 1950. from very dry to wet. And every experimental design is repeated more than 3-times. This experimental de- (i) Hebei. Hebei has good instrumental observation sign follows up to the observation method (see also ref. data at the period of 1911―1950. The instrumental [12]) of Yu Fen Cun in the Qing Dynasty, so the rela- precipitation data in Taiyuan and Jinan began at 1916. tionship equation between rainfall and depth of infil- The instrumental precipitation data in (began tration can be used to reconstruct precipitation in the at 1914) and (began at 1900) well related to Qing Dynasty in terms of Yu Fen Cun, and it can be Shijiazhuang and Cangzhou, respectively. Depending expressed as on the correlation (Ps = 0.6553Pb + 185.22, r = 0.74; P = 0.947P + 62.375, r = 0.737, where P , P , P , P P= 1.6882×10−4 Z 2+0.1298 Z , (4) c t s b c t r f f indicates the precipitation in Shijiazhuang, Baoding, where Pr indicates artificial rainfall, Zf indicates the Cangzhou and Tianjin station, respectively), the an- depth of infiltration, the sample size is 41, and the nual precipitation in Shijiazhuang and Cangzhou can multiple linear correlation coefficient R = 0.9325. Eq. be worked out at the period of 1911―1950. Then, the (4) can correctly reconstruct the precipitation with the precipitation series of 1911―1950 in Hebei is avail- 2 high variance explanation R = 87%. Compared with able by calculating the mean of four stations. Note that seasonal and annual precipitation using the two meth- annual precipitation of 1911―1915 in Taiyuan, Jinan ods, relative errors of them are 2.0% (spring), 3.4% and annual precipitation of 1911―1913 in Shijia- (summer), 2.1% (autumn) and 2.9% (year), respec- zhuang needs to be interpolated firstly as described in tively, which suggested small difference between both section 3.2. of the models (see also ref. [12]), and further proved the reliability of physics model. Thus, it also means (ii) Jinnan. Only Anyang has instrumental precipita- that reconstruction precipitation is reliable using tion data begun at 1919. The precipitation in Jinnan is physics model in the middle and lower reaches of the calculated by regression equation (Pav = 0.5774Pa + 213.38, r = 0.874, where P indicates sub-regional Yellow River with soil physics characteristic similar to av precipitation, P indicates precipitation in Anyang) Shijiazhuang. a between Jinnan and Anyang. 2.3 Precipitation reconstruction for sub-region dur- (iii) Weihe. During 1911―1950, only Xi’an has in- ing 1911―1950 strumental precipitation data which began at 1923. At the period of 1911―1950, the snow and rainfall The precipitation in Weihe is calculated by regression archive records are ended, and the instrumental equation (Pav = 0.7928Px + 80.427, r = 0.8323, where observation data are fragmentary, so we reconstruct 4 Pav indicates sub-regional precipitation, Px indicates

2190 Science in China Ser. D Earth Sciences precipitation in Xi’an) between Weihe and Xi’an. from Morlet wavelet transform indicates that 80-year scale wavelet coefficient “time stream” shape (figure Since there is no observation data available in Jin- omitted) is similar among the 4 sub-regions, but in the nan and Weihe for some years, such as 1911―1918 in different sub-region, the wavelet signal has not only Jinnan and 1911―1922 in Weihe, the annual precipi- different weak or strong fluctuations, but also different tation of these years in Jinnan and Weihe needs to be phases. In which, the 80-year scale fluctuation signal interpolated as mentioned in Section 3.2, for keeping of Shandong is strong through the last 300 years, but series continuity. for other 3 sub-region, especially in Jinnan and Weihe, (iv) Shandong. The instrumental precipitation data the 80-year signal is weak before 1850, and it becomes began at 1898 and 1888 in and , re- stronger and stronger after 1850. Moreover, the time spectively, but both of them are located at the coastal reaching to peak (raininess) or valley (rainless) is dif- area, and the single site is lack of good regional spatial ferent for each wave in different sub-regions. This re- representation. Therefore, the precipitation series of sult further proved that the change trend in the middle 1911―1950 in Shandong is calculated by regression reaches is different from the lower reaches of the Yel- equation (Pav = 0.4739Pqy + 380.2, r = 0.6209, where low River. (2) There are 11 rainy decades of 1741― Pav indicates regional precipitation, Pqy indicates the 1750, 1761―1780, 1791―1820, 1821―1830, 1851― average precipitation in the 2 stations of Qingdao and 1860, 1881―1890 and 1951―1970 in 3 sub-regions Yantai) between precipitation of Shandong and aver- or above, especially in 1791―1800, 1821―1830 and age precipitation of Qingdao and Yantai. To be ex- 1881―1890; rainless decades happened at 1781― plained that, the variance explanation (R2 = 38.55%) of ― ― ― the regression equation is lower than that of other 3 1790, 1831 1840, 1861 1870, 1891 1950 and sub-regions, but the reconstruction process is rela- 1981―2000, especially at 1911―1950 and 1981― tively reasonable contrasted with the interpolation 2000, which indicates that precipitation has simulta- method of drought/flood index. neously increasing or decreasing features in 3 sub- regions at least. (3) The variation of precipitation in The above conversion calculation or interpolation Shandong sub-region is opposite to that in other 3 sub- does influence data precision for this period, but in regions, but PCA shows that variance contribution of order to keep the series continuity, it is a reasonable the first principle component (consistent trend in 4 data processing without other rainfall data available. sub-regions) reaches to 54.3%; meanwhile, the corre- Furthermore, these derived data cannot change the lation coefficients of precipitation series between each climate trend. sub-region and whole region are 0.7169 (to Weihe), 3 Analysis on variation of precipitation 0.7711 (to Hebei), 0.6864 (to Shandong), 0.7441 (to Based on the aforementioned methods and results, 4 Jinnan), with a 1% significance level, which proved sub-regional mean precipitation series of 1736―2000 that the mean precipitation series from the 4 sub-re- can be reconstructed by calculating the mean of all gions can mirror the precipitation change trends over stations in every sub-region at both periods of 1736― the middle and lower reaches of the Yellow River. 1910 and 1951―2000, joining with the precipitation The decrease tendency is shown in Fig. 4(e) for the for 4 sub-regions at the periods of 1911―1950. And last 300 years over the middle and lower reaches of then the precipitation series over the middle and lower the Yellow River. Before 1915, the rainy years are in reaches of the Yellow River can be established by cal- majority (the years, in which the precipitation is higher culating mean precipitation of the 4 sub-regions (Fig. than mean of the series, account for 54% of all), and 4). It shows that (1) precipitation anomaly trend in the precipitation is clearly high with longer duration Shandong is opposite to that in other sub-regions at the especially for the three periods of 1791―1805, periods of 1751―1830 and 1861―1880. The result 1816―1830 and 1886―1895. And there is remarkable

Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River 2191

Fig. 4. Annual precipitation series of the middle and lower reaches of the Yellow River and its 4 sub-regions. (a) Hebei; (b) Jinnan; (c) Weihe; (d) Shandong; (e) average of 4 sub-region. Slim line: annual precipitation; thick line: 10-years moving average; dashed line: mean value. low in the precipitation at 1811―1820, 1831―1840, Meanwhile, Shanxi, Henan and Shaanxi Province are 1875―1882 and 1896―1905. It is worth noting that in serious drought, the farmer is praying the rain rev- 1) the most extreme drought event of the last 300 years erently” . “It is extremely drought, migratory locust 2) happened in 1877, which indeed arrested Emperor’s disaster occurred in Zhili Province too…” . “Shaanxi attention. In the imperial edicts of Emperor Guangxu, Province in drought and barren for a long time. Un- the severity and spatial coverage for this event had fortunately, the extreme drought has also occurred in 3) been mentioned time and again. For example, “This Shanxi, Henan and Shaanxi provinces this year” . year (1877), although it rains in Zhili Province since These records further proved that the drought event the autumn, the total amount is not enough at all. occurred in the most of middle and lower reaches of

1) Imperial edict on the 2nd, the ninth month in lunar calendar, the third year of Guangxu Emperor (Oct. 8, 1877). 2) Imperial edict on the 16th, the seventh month in lunar calendar, the third year of Guangxu Emperor (Aug. 24, 1877). 3) Imperial edict on the 18th, the ninth month in lunar calendar, the third year of Guangxu Emperor (Oct. 24, 1877).

2192 Science in China Ser. D Earth Sciences the Yellow River, apart from Shandong. However, af- reconstruction method has specific physical signifi- ter 1915, the rainless years are in majority (the years, cance, and the reconstruction procedure is objective, in which the precipitation is lower than mean value of which would be accepted easily by the international the series, account for 66% of all). Except for the pe- academia. Furthermore, historical precipitation recon- riod of 1946―1965, the climate is in the rainless pe- struction from Chinese historical documents would be riod in other decade. very helpful for the global change study. Mann-Kendall test detects that the abrupt climate (2) The seasonal precipitation at 17 stations over the change from high to low of the precipitation occurred middle and lower reaches of the Yellow River is re- around 1915 over the whole region, which agrees with constructed during the period of 1736―1910, and the the other study result of abrupt change occurring in the precipitation series of the middle and lower reaches of 20th century[18―21]. In which, there exists an 80 mm the Yellow River and its 4 sub-regions are established difference of the 5-year mean precipitation before and extending to 1736. Analysis of these precipitation se- after 1915. It is worthwhile to pay more attention to it ries indicates that the abrupt change of precipitation in the future study because of the water resource be- from high to low occurs around 1915 over the middle coming shorter and shorter in this area. and lower reaches of the Yellow River. During the three periods of 1791―1805, 1816―1830 and 1886― In addition, Power Spectral Analysis (max. lag = 88, 1895, the precipitation is marked higher than the mean figure omitted) shows that the precipitation has sig- of the series. While both the periods of 1916―1945 nificant periodicity of 22―25a, 3.9a and 2.7a in the and 1981―2000 are characterized by less precipita- past 300 years over the middle and lower reaches of ― the Yellow River, which related to the solar and ENSO tion. Three periodicities of 22 25a, 3.9a and 2.7a are activities probably. Furthermore, the analysis of Mor- shown in the precipitation fluctuation over the middle let wavelet transform indicates that the periodical sig- and lower reaches of the Yellow River. Moreover, the ― nal of 22―25a becomes weaker and weaker since the periodical signal of 22 25a becomes weaker and weaker since the abrupt change of 1915 and disap- abrupt change of 1915 and disappears in the late 1940s, pears in the late 1940s, then the periodical signal of then the periodical signal of 35―40a appears instead. 35―40a appears instead. These results would be vital This feature is vital to the future precipitation projec- to the future precipitation projection, water resource tion in this area. utilization and social-economical development in this 4 Conclusions area.

(1) The snow and rainfall archives in the Qing Dy- Acknowledgements We would like to take this opportunity to ex- nasty can be used to reconstruct the historical seasonal press our appreciation to anonymous referees for the critical review and useful comments. We also thank Prof. Wei-Chyung Wang to polish this precipitation series with the high-resolution and quan- paper. This study was supported by the Key Project from the National titative records, based on the surface water balance Natural Science Foundation of China (Grant No. 40331013), as well as the project from the Chinese Academy of Sciences (Grant No. KZCX3- equation and soil physics model, together with obser- SW-321). vation data of precipitation and field soil moisture References content. Meanwhile, the reconstruction series in Shijia- zhuang derived from field experiment also further 1. Eddy, J. A., The PAGES project: Proposed implementation plans validates the reliability of soil physical model for research activities, Global Change Report No. 19, Sweden, Stockholm: IGBP, 1992, 1―112. reconstruction. In this study, we not only develop the 2. Duplessy, J. C., Overpeck, J., The PAGES/CLIVAR Intersection: method for quantitative precipitation reconstruction Providing Paleoclimatic Perspective Needed to Understand Cli- based on the snow and rainfall archive, but also design mate Variability and Predictability. Switzerland, Bern: PAGES Core Project Office, 1994, 9. actual arithmetic and select related parameters derived 3. Bradley, R. S., High Resolution Record of Past Climate from from observation and experimental data. Thus, the Monsoon Asia: The last 2000 years and beyond, Recommenda-

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