Were there any large animals in ancient China?

(1) Neolithic Age to Shang Dynasty-warm and humid environment.

The Neolithic Age is an important stage in the development of human history, which is about/kloc-0.0 million years ago. During this period, the development of the earth entered the Holocene after the last ice age of Pleistocene. After that, the climate continued to warm, which was the Holocene warm period or the best suitable period of Holocene. This period is also called "Yangshao Warm Period" because it has certain connection with Yangshao Cultural Period. In academic circles, the research group headed by Academician Shi Yafeng thinks that the Holocene Great Warm Period in China occurred between 8500 and 3000 years ago [1]. This is a relatively accurate data, and it can also be used as the beginning and ending period of "Yangshao Warm Period". This just corresponds to Peiligang in the middle and lower reaches of the Yellow River in China-magnetic mountain culture, Yangshao culture, Longshan culture and Xia and Shang dynasties.

The early Neolithic period was about 10000 ~ 7000 years ago, corresponding to the early "Yangshao Warm Period". The middle Neolithic period, about 7000 ~ 5000 years ago. Late Neolithic period, about 5000 ~ 4000 years ago. Yangshao warm period is a suitable temperature period, agriculture began to sprout and develop rapidly, and the country began to be established, which laid a civilized foundation for the prosperity of Neolithic culture era and the development of the Chinese nation.

In the early Neolithic period, about 10000 ~ 7000 years ago, the climate in the Central Plains was in a transitional stage from the late glacial period to the post-glacial period. Although the climate is still cool and dry, it is getting warmer gradually, which has obvious transitional characteristics.

Throughout the lower reaches of the Yellow River, the pollen content of conifers decreased significantly, while that of broadleaf trees increased. Some warm-loving genera and species, such as Quercus, began to appear, but the sporopollen assemblage was still dominated by conifers, and the vegetation type was coniferous and broad-leaved mixed forest. This period lasted about 2000 years. The transitional characteristics of vegetation in the lower reaches of the Yellow River during this period show that the temperature in the Central Plains showed an upward trend in the early Neolithic period.

Magnetic mountain culture site dates back to 5405-5285, mainly distributed in central and southern Hebei, north to the southern foot of Yanshan Mountain, and south to Anyang area in northern Henan Province. According to Mr. Zhou Benxiong's identification, the animal specimens of Cishan site can be divided into five categories: mammals, birds, turtles, fish and mussels, which can represent at least 23 species of animals such as Northeast Zokor, Mongolian rabbit, macaque, badger, masked raccoon, leopard, canine, domestic dog, sika deer, red deer, four elephant deer and roe deer. Among the above animals, dogs, pigs and chickens are domestic animals, cows are not necessarily domestic animals, and the rest are wild animals. The roe deer, commonly known as roe deer, generally lives in the reeds along the river bank, in the forest near the lake or on the mountain side, and is mainly distributed in the provinces of the Yangtze River basin today. Wild boar, macaque, beaver, etc. Can explain that there are many aquatic plants and dense forests not far away. The discovery of a large number of Pu Shu seeds and carbonized pecans also proves this point. In particular, the discovery of macaques shows that the area near the foothills of North China Plain in Neolithic Age was covered by forests, and the distribution of macaques was farther north than in modern times. Beaver is a species in tropical and subtropical regions. The discovery of the remains of aquatic animals such as grass carp, soft-shelled turtle and mussel shows that Nanming River once had a wide water area, a large flow and rich aquatic products [1]. These archaeological discoveries show that the environment at that time should be wide waters and warm and humid climate.

In addition, according to the pollen analysis of Jiahu site of Peiligang culture, although there are a few warm-loving plants such as Populus, Rubiaceae, Euphorbiaceae and Polypodiaceae. There are no elms and oak trees in the sporopollen assemblage of the underlying loess layer of Peiligang culture in Jia Hu. Drought-tolerant Artemisia, Compositae and Chenopodiaceae are dominant, indicating that the temperature has risen a lot since the last glacial period, but it is not very high and the precipitation is not great. On the surface of the underlying stratum, that is, the sporopollen assemblage on the ground when Peiligang people first came to this activity, the thermophilic factor further increased, such as elm, Liquidambar formosana, Zelkova schneideriana, water fern and so on. Newly emerging, and the proportion of Salix and Quercus has also increased, the proportion of Cyclospora has increased, while the proportion of Artemisia and other plants has decreased by more than 50%, showing a trend of decreasing the grassland area of Artemisia and expanding the lake area. The climatic conditions reflected may be similar to or slightly warm and humid, belonging to a mild and semi-humid climate. During the period of Peiligang culture, a large number of animals such as crocodiles, turtles, roe deer, etc. Appearing in the Yangtze River basin and its south area, the proportion of cyclosporine increased and the proportion of Artemisia decreased, reflecting the trend of further shrinking grassland area and further expanding lake and marsh area, indicating that the temperature and precipitation at that time were higher than today's area, showing warm and humid climate characteristics, similar to the present Yangtze River basin [65438

All these indicate that in the early Neolithic period, the climate changed from dry and cold to warm and humid, and the temperature and precipitation increased. In the period of magnetic mountain culture and Peiligang culture, the climate turned warm and humid, and the ecological environment improved obviously.

The middle Neolithic period is about 7000 ~ 5000 years ago. During this period, the climate in the Central Plains was generally characterized by warmth and humidity.

According to the pollen analysis of T37 cultural layer profile with a thickness of 9.7m in Dahecun site, there are 26 plant families and 9 spore types, namely: Pinus, Betula, Quercus, Ulmus, Juglans, Chenopodiaceae, Artemisia, Compositae, Gramineae, Cyperaceae, Ranunculaceae, Labiatae, Polypodiaceae, Selaginaceae, etc. According to the analysis of these sporopollen assemblages and their changes in the longitudinal section of the site, the number of woody and herbaceous pollen and fern spores is about 9.4 meters, of which shrub and herbaceous pollen account for 53.7% of the total sporopollen; Arbor pollen accounts for 45.6%, and fern spores only account for 0.7%. Up to 9.4 ~ 3.8 meters, woody plant pollen is dominant, accounting for 84. 1% of the total sporopollen, followed by vegetation plant pollen. 3.8 ~ 1.5 m, shrubs and herbs are dominant, and no spores are found. From 1.5 meters to topsoil, woody plant pollen is higher than herbaceous plant pollen, and there are many spores, most of which are lycopodium spores. In the woody plant pollen, from the proportion of coniferous, broadleaf and shrub pollen, coniferous pollen is more than broadleaf pollen, accounting for more than 90% of the total woody plant pollen at most, while broadleaf pollen is less, accounting for 22.2% of the total woody plant pollen at most, mainly including birch, oak, elm, linden and walnut. However, shrub plants have little pollen. At the bottom, bottom and top of the profile, there are fewer species of herbaceous pollen and more species in the middle. Except for a large number of Gramineae pollen at 9.4m, the rest are Artemisia and Chenopodiaceae pollen. Judging from the above sporopollen assemblage, there are a considerable number of woody plant pollen and a certain number of herbaceous plant pollen, the former is often more, which shows that there should be forest and grassland vegetation at that time. There are a large number of annual or perennial mesophytes and xerophytes such as Chenopodiaceae, Artemisia, Gramineae, Compositae, Ranunculaceae, Cruciferae and so on. , there are a small number of birch, elm, oak and other broad-leaved trees dotted among them. Some wet and aquatic herbs and spore plants, such as Gramineae, Cyperus and Pteris, grow on the banks of rivers and ponds. There are a large number of coniferous species of Pinus and a small number of broad-leaved species of elm, oak, walnut, linden, etc. on the hills and hills far and near, and spore plants such as shrubs, ephedra, grasses, compositae, Polypodiaceae, Selaginella, etc. grow under the forest and on the forest edge, indicating that the place far from Dahe Village was covered by forests at that time, and shrubs and grasses were distributed nearby. From the remains of fish, raccoons, badgers, cattle, deer, muntjac, pigs, bamboo rats and other animals found in Dahecun site, it shows that there were groups of wild animals in dense forests, overgrown with weeds and bamboo forests, and tail fish were common in rivers and lakes. [ 1]

Some scholars have also come to the conclusion that the winter in Yangshao period in Dahe Village was warmer and the annual precipitation was more than it is now, according to the popular plastic burning construction technology and cultural relics unearthed in Dahe Village, such as lotus seeds, snail shells, clam knives and clam sickles. Combined with the found animal bones such as raccoon, muntjac and bamboo rat, it is pointed out that the normal growth of bamboo can only be satisfied if the annual precipitation is greater than 1 000 mm, so the annual growth at that time is estimated. [ 1]

The animal bones unearthed from Xiawanggang site in Xichuan County, Henan Province also prove the warm characteristics of the Central Plains in the Neolithic Age. Xiawanggang Site is located on Hongshigang in the north of Xiawanggang Village, about 35 kilometers south of Xichuan County, with an area of about 6,000 square meters, generally 2-3.5 meters thick and some about 4 meters thick. There are nine cultural layers, including Longshan culture, Qujialing culture and Yangshao culture in the Western Zhou Dynasty, Pre-Shang Dynasty and Neolithic Age. In Xiawanggang site, 3 1 species of animals were found. Judging from their current distribution range, there are 1 1 species of animals, such as peacock, macaque, giant panda, Suman rhinoceros and Asia. The rest are adaptive animals visible in the north and south of the Yangtze River, accounting for 6 1.29% of the total. It should be pointed out in particular that in this batch of materials, the species of animals found in the seventh to ninth cultural layers (namely Yangshao cultural layer) are the most abundant, with a total of 24 species, of which 7 species are warm-loving animals, accounting for 29. 17%, and the rest are highly adaptable animals, accounting for 70.83%, and the proportion of warm-loving animals is the largest. [ 1]

Late Neolithic period, about 5000 ~ 4000 years ago, represented by Longshan culture, the climate in this period was still warm and humid.

The fourth cultural layer of Xiawanggang in Xichuan is the Longshan culture period, in which there are remains of warm-loving animals. Among them, the water deer specimen and the axis deer specimen are new species, but this kind of water deer is only produced in Sichuan, Yunnan, Guangdong and Taiwan Province provinces in China, as well as Sumatra, Java and Galiman Dan. This kind of deer is now distributed in Bengal, Indian zhina, Myanmar and Thailand. There are 9 species of animals unearthed in the Longshan cultural layer of Xiawanggang, among which 22.22% are warm-loving, 65,438+065,438+0.65,438+065,438+0% are cold-loving, and the rest are adaptable animals, accounting for 66.66%. [1] This shows that in the Longshan culture era, animals in the Central Plains.

155 sporopollen (sample number: q Ⅱ LSH) were found on the selected section of Duangang Longshan cultural layer in Qixian county. The pollen content of herbaceous plants accounted for 65.8% of the total sporopollen, mainly Humulus scandens, Artemisia, Chenopodiaceae, Malvaceae, Gramineae and a few Cruciferae and Typha. The spores of pteridophytes account for 365,438 0.6% of the total sporopollen. In China, they are mainly Polypodiaceae, Lycopodiaceae and Pteridaceae. Woody plant pollen is a small amount of Pinus and Betula, accounting for only 2.6% of the total sporopollen. It constitutes the sporopollen assemblage of Cao Ping-Dugan-Songshui keel-Lycopodium. The appearance of herbaceous pollen and fern spores is a reflection of humid climate, and a large number of water keel ferns indicate a warm and humid growth environment. [ 1]

Since the Neolithic Age, the warm and humid climate in the Central Plains continued until the middle and late Yin and Shang Dynasties. According to the research and identification of animal bones unearthed from Yinxu site in Henan Province by De and Yang, these bones include 29 species of animals, among which animals living in subtropical areas include roe deer, bamboo rat, rhinoceros, elephant, tapir and sacred buffalo. In addition to the above animals, we can also see two kinds of animals, pheasant and sturgeon, in the reports of animal remains in Yin Ruins. The former is currently only distributed in mountainous areas such as Yunnan, Guangxi and Hunan, while the latter is presumed to be a kind of Chinese sturgeon or sturgeon, both of which are produced in the Yangtze River basin. [1] Mr. Zhu Kezhen also pointed out that the rice planted in Anyang at that time began to be planted in February or March of the lunar calendar, that is, March of the solar calendar; It is about one month ahead of the current planting in Anyang to mid-April. [1] According to Mr. Zhu, the annual average temperature in China was about 2℃ higher than it is now, and the monthly average temperature in/kloc-0 was about 3℃ ~ 5℃ higher than it is now. According to this inference, the temperature in Anyang and Linxian in the north of western Henan at that time was similar to that in Xinyang and Nanyang today, and they all belonged to the subtropical zone. [ 1]

(2) From the end of Shang Dynasty to the Western Zhou Dynasty, the climate changed gradually.

The climate of the Western Zhou Dynasty is mainly characterized by drought and cold. Especially in the late Western Zhou Dynasty, Li, Xuan and Zhou Dynasties, the climate in the middle reaches of the Yellow River was severely dry, with severe droughts in successive years, dry ponds, barren land and dead forest plants. Climate and environmental resources are relatively bad periods in history.

At the end of Shang Dynasty (3 100 years ago), the climate in the middle and lower reaches of the Yellow River began to deteriorate, and the climate characteristics changed from warm and humid to dry and warm. [1] The ancient version of bamboo slips said that it was written to be "three times a day" for three years, and Mozi didn't attack. This version of bamboo slips said that it rained sparingly during the week (Bo), and "Mandarin Zhou Yushang" contained "Yesterday's Iraq. All these indicate the drought of the climate at that time. Although the climate is dry, it is still in a warm period. According to Oracle Bone Inscriptions and literature, there were rhinoceros, elephants, deer and other heat-loving animals.

However, this situation did not last long. Mr. Zhu Kezhen also pointed out that "the climate of the Zhou Dynasty, although warm at first, quickly deteriorated". [1] The ancient bamboo book records that "seven years, winter rain and hail were as big as plums". This edition of Bamboo Records records that in the winter of seven years, Xiao Wang was "raining cats and dogs, cattle and horses died, and Jianghan moved (frozen)". Four years in Wang You, "Summer and June, first frost". "Peach and apricot fruit" in autumn and September of ten years. "Poem Xiaoya First Month" also records that "the first month is full of frost, and my heart is sad". These records all show the cold climate in the middle reaches of the Yellow River during the Western Zhou Dynasty.

Due to the cold climate, rhinoceroses, Asian elephants, sacred buffaloes, bamboo rats and many other animals that love heat began to migrate south. For example, the ancient book "Annals of Bamboo Books" records that "in the sixteenth year of Wang Zhao, he cut Jingchu, involved in Han, and encountered great difficulties." This is a female rhinoceros. There are fewer and fewer rhinos in the Central Plains. (King of Iraq) "Hunting in Turin and getting a rhinoceros".

According to the literature, the drought in Zhou Liwang period began to appear and lasted for 150 years. This edition of bamboo book records the drought in Li Wang in 22 years, 23 years, 24 years, 25 years and 26 years. After Wang Xuan ascended the throne, this rare drought did not stop, but continued year after year. For example, it is recorded in [1] that: "When the two sides set up Xuanwang, there was a great drought." Huangfu Mi's "Emperor Century" also recorded that "in the first year of Wang Xuan, there was a drought all over the world and it rained for six years". [1] Severe drought has caused vegetation to dry up, rivers to dry up, and even many people died of drought, which shows the seriousness of drought. In the second year of Zhou Youwang, "Three Rivers dried up and Qishan collapsed", and the drought [1] continued until the demise of the Western Zhou Dynasty.

In addition, from the archaeological discoveries and sporopollen combination analysis in the Western Zhou Dynasty, we can also see the climate at that time. According to the plant ecological characteristics of pollen genera and species at different levels in the loess profile of the middle reaches of the Yellow River, we can infer the vegetation and climate conditions at that time. In the stratigraphic sections of Luochuan, Wugong and Qishan in Shaanxi Province, there are often woody pollen such as oak, elm, maple, walnut and Ailanthus altissima in the paleosol layer, and even woody pollen such as lacquer, chestnut, osmanthus fragrans, Pterocarya stenoptera, Liquidambar formosana and Carya cathayensis in the subtropical zone, indicating that they were formed in the temperate broad-leaved forest environment. In the loess layer, these trees are very rare, while the pollen components of chrysanthemum, Artemisia annua and sunflower are extremely prominent, indicating that they were formed in grassland and desert grassland environment. [ 1]

From the above materials, it can be seen that the climate in the Western Zhou Dynasty was dry and cold, and the climate in the Eastern Zhou Dynasty was also reflected in the literature. Most of them recorded that the central plains region was dominated by cold feeling at that time. For example, in Historical Records of Qin Shihuang, there was a heavy snow in Xinzheng in the twentieth year of Qin Shihuang, which was 2 feet and 5 inches thick. It should also be relatively cold.

(3) Qin and Han dynasties-the climate is similar to today.

The climate in Qin and Han Dynasties is not much different from that in Central Plains today. Mr. Wen Huanran made an in-depth analysis of the climate in the middle and lower reaches of the Yellow River in Qin and Han Dynasties from the changes of cold and warm, dry and wet. He thinks: "The temperature change in the middle and lower reaches of the Yellow River in Han Dynasty shows no signs of cooling", "The rainy periods in Han Dynasty also appear alternately, and the degree of rainy periods in each period is different", "The rainy periods appear alternately, and there is no obvious phenomenon of getting wet or dry". "To sum up, the climate change in the middle and lower reaches of the Yellow River in Han Dynasty is indeed different from that in modern times, but it is not in line with what Meng and Hu Houxuan said, and it is also somewhat different from Zhu Kezhen's pulse theory; In fact, it is not much different from modern times. " [ 1]

First of all, as far as the ice age of rivers is concerned, according to the records in Lu Dongji and Huai Nan Zi Shi Zexun, Mr. Wen Huanran thinks that the water and soil of the Central Plains in the Qin and Han Dynasties have frozen at least in October of the lunar calendar. However, Lu Lan Qiu Zhong Ji and Huai Nan Zi Shi Zexun recorded that the interception date in Qin and Han Dynasties was mid-winter, that is, the so-called "(mid-winter) ice is firm, and the mid-winter is the lunar calendar 1 1, while Cui Ai's" four-person monthly order "[1] was based on the Henan Meteorological Bureau. The first ice in Zhengzhou area is about1October15 per year, the final ice is about March 12, and the ice age is about 1 16.8 days. So we can see that the climate between Qin and Han Dynasties and today is not very different. [1] During the Qin and Han Dynasties, the "light snow" in the 24 solar terms was taken as the beginning of the average first snow period in the middle of the Yellow River Basin, and the first frost was taken as the average last snow period, so Lun Heng Bian said that "the frost and snow in Zhongzhou fell in February in the first month, and it was cold in the north and cool in March." It can be seen that during the Qin and Han dynasties, the snow broke in March in the Central Plains, and the snow period lasted for five months. [1] Today, the average first snow period in the middle of the Yellow River Basin is165438+1late October, which is not much different from the middle of the lunar calendar in Qin and Han Dynasties. [ 1]

Secondly, the date of the hot season is also very consistent with the Qin and Han Dynasties. During the Qin and Han Dynasties, the middle of June in the lunar calendar was the hottest period in the middle of the Yellow River Basin, and beginning of autumn was later than the summer heat, or in late June. Therefore, the hottest period in the Central Plains during the Qin and Han Dynasties is about the end of June or the beginning of July of the lunar calendar, which is no different from the average temperature in Xi and Zhengzhou today, and it is the highest in July of the solar calendar. [ 1]

Finally, the emergence of dry season and rainy season in the Central Plains during the Qin and Han Dynasties was roughly the same as it is now. The spatial distribution of precipitation in the middle and lower reaches of the Yellow River in Qin and Han Dynasties was quite different. The first area between the Yangtze River and Huaihe River is mainly in the southeast near the lower reaches of the Yellow River, which is equivalent to the southeast and south of the Central Plains today. During the Qin and Han dynasties, the precipitation in this area was mostly concentrated from late May to early June of the lunar calendar. Therefore, Shu Yao Volume III quoted Cui Ai's Four-person Monthly Order, saying, "After the tent was set in May, the rain fell and rice and firewood were accumulated to prepare for the road subsidence. Second, the northern part of the lower reaches of the Yellow River is equivalent to the northern part of the Central Plains today, and its precipitation is mostly concentrated at the turn of summer and autumn. Third, the middle reaches of the Yellow River, including today's western Henan, mostly concentrate on the precipitation in August of the lunar calendar, so it is said in Hanshu Shihuozhi that farmers in this area "don't take shelter from the rain in autumn". Han Shugou said: "The river is not guarded, small water flows in, and the vicious obstacles are low. I think that pollution makes the autumn water rest, swimming from side to side, and relaxing. "Therefore, Mr. Wen Huanran believes that the regional differences between the dry season and the rainy season in Qin and Han Dynasties are similar to those in today's river basins, indicating that the overall situation of precipitation in Qin and Han Dynasties is not significantly different from today's. [ 1]

(4) Wei, Jin, Southern and Northern Dynasties to Sui and Tang Dynasties-alternating cold and warm climate.

During the Wei, Jin, Southern and Northern Dynasties, the climate in the Central Plains was mainly cold and dry, which was not only reflected in agricultural phenology, but also in some extreme cold events. In official records, cold feelings such as heavy snow, frost and heavy rain are common in the Central Plains.

According to the reflection of Shu Wei Wendy Ji, in the sixth year (225), I visited the old town of Guangling in winter and watched soldiers on the river, with more than 100,000 soldiers and hundreds of flags. It was a cold year, and the waterway was frozen. The ship was not allowed to enter the river, but it was brought back. " Mr. Zhu Kezhen thinks that this is the first recorded freezing of Huaihe River that we know. It was colder then than now. [1] Another cold event in which Huai Si was completely frozen was also recorded in Zi Tong Zhi Jian 148. In the winter of the 14th year of Tian Jian (May1May), the climate in the Central Plains was cold, and not only Huaishui and Surabaya were frozen again, but also most soldiers at Fushan Weir were frozen to death. Therefore, the history book records: "It was winter, it was very cold, Huai Si was completely frozen, and the foot soldiers died in Fushan weir."

Agricultural production is closely related to climate. From 533 to 544 AD, the book "Qi Yaomin's Book Planting Valley" written by Jia Sixie in the Northern Dynasty recorded: "In early March, peach blossoms were in full bloom in Tomb-Sweeping Day, and in early April, jujube trees grew leaves and mulberry flowers fell." Compared with now, the phenology in spring is delayed by ten days to half a month, that is, the temperature in spring is lower than that in modern times, which is obviously a cold period phenomenon. In addition, Qi Yaomin's Pomegranate in An Shu records: "In mid-October, it was wrapped in yarn (if it was not wrapped, it would freeze to death) and it was liberated in early February." Now pomegranate trees in Henan, Shandong and other places can overwinter in the open field without being buried, which shows that the temperature in that winter was colder than now. Su: "Always remember to plant trees every day in October, November and December, and note from the cloud:" Those who freeze trees are sealed with frost. " This phenomenon of freezing trees is the modern fog. Jia Sixie used this as an indicator of the next year's suitable date for sowing millet, which indicated that the temperature was low at that time.

Not only in the Central Plains, but also in the Wei, Jin, Southern and Northern Dynasties, the whole Huanghuai Plain was extremely cold. This cold period can be roughly divided into two cold low-value periods. The first cold low value period appeared in the first 10 year from the 1970s to the 4th century, and lasted for about 40 years. The most important feature of these 40 years is the high frequency of cold events, which undoubtedly shows the cold fluctuation of climate in these 40 years. After the first cold period passed, the second cold period on the Huang-Huai-Hai Plain showed signs at least in the early years of the Northern Wei Dynasty, and the second cold process that began in the Wei and Jin Dynasties continued until the 1920s. [ 1]

Sui and Tang Dynasties is an important stage of climate change in China in recent 5,000 years. This period belongs to the third warm period in the four-warm and four-cold model classified by Zhu Kezhen, that is, 600 ~ 1000 years, which is generally called the Sui and Tang Dynasties warm period. Later, the academic circles made a further in-depth discussion on Zhu's research, and thought that the climate fluctuated from warm to cold during the warm period of Sui and Tang Dynasties, and there were also relatively cold periods, but overall, the climate of Sui and Tang Dynasties was still warmer.

From the phenological point of view, Gong Gaofa and others think that the northern boundary of subtropical zone in the warm period of Sui and Tang Dynasties moved northward 1 0 ~1latitude than it is now, based on the phenological evidence that plum trees are distributed in the middle and lower reaches of the Yellow River, oranges in the middle and lower reaches of the Yangtze River are basically free from freezing damage, and the spring phenological period is15 days earlier than this morning. [1] Based on archaeological excavations and records of droughts and floods in past dynasties, Mr. Wang Yi studied and obtained the climate change curve in the Central Plains in the past 5,000 years with the unit of annual precipitation (wet and dry) by means of historical research and modern analysis. He believes that since the unification of Qin and Han Dynasties, the Central Plains has experienced nine periods of drought and little rain and eight periods of long wet and rainy for more than two thousand years, and it is still in the drought part of the period of little precipitation. The rainy season and the dry season always alternate. However, the rainy season and dry season are long and short, and their amplitudes are high and low. Specifically, since the Western Zhou Dynasty, there have been a series of rainy and dry periods in the Central Plains, but the rainy and dry periods are long and short, and the severity of the wind and dry periods is also different. The worst dry period is from 870 BC to 72 BC1year, that is, from the late Western Zhou Dynasty to the early Eastern Zhou Dynasty. At this time, it is an era of peace and tranquility. The wettest and wettest period was the Tang Dynasty from 630 to 800. As shown in figure [1]:

According to the Map of Precipitation Change in the Central Plains in the Last Five Thousand Years drawn by Mr. Wang Yi, there was a rainy season in the Central Plains during the Sui and Tang Dynasties, which lasted for nearly 200 years. During the rainy season, the amplitude was high, reaching the second level of rainfall represented by the ordinate, that is, wet and rainy. From the change process of precipitation and temperature in the Central Plains since the late Holocene, there is an obvious positive correlation between precipitation and temperature in this area. That is, the climate in the warm period is rainy and humid; On the contrary, the climate is dry and there is little rain in cold periods. The correlation analysis between the observed temperature and precipitation in Henan province 1 1 city for more than 30 years also shows that there is a good positive correlation between the temperature and precipitation, which accords with the basic characteristics of the East Asian monsoon climate in China. [1] Therefore, the view that the climate was warm and humid during the Sui and Tang Dynasties is reasonable.

(5) From the end of Tang Dynasty to Song Dynasty, climate change experienced a process from warm to cold.

From the late Tang Dynasty to the middle and late Northern Song Dynasty, the Central Plains region was always in a warm period, and the climate in the late Northern Song Dynasty turned into a new cold period in China's historical period.

There are 49 years in the historical records such as History of Song Dynasty and Records of Five Elements that there is no ice and snow or the climate is warmer in Kaifeng in winter, which obviously exceeds the winter cold record of 3 1 year in the same period. As for the recording frequency of warm winter, its proportion is higher. This shows that Kaifeng was in a warm winter period. Although there are many reasons for the lack of snow or snowfall in winter in Kaifeng, most of them are due to the high temperature and the lack of strong cold air. Therefore, some scholars pointed out that "the study of fitting the temperature curve since China 1000 with extremely warm and extremely cold events was obviously warmer in the Northern Song Dynasty" [1]; "Most of the records of little or no snow in winter in the historical materials of the Northern Song Dynasty should correspond to the phenomenon of warm winter" [1]. A large number of records about this climate show that Kaifeng's climate was in a relatively warm period in the Northern Song Dynasty. In the historical materials of the Northern Song Dynasty, there are also many records of praying for snow, such as Jiayin in December of the first year of Gande, and Taizu "ordered a close minister to pray for snow"; On the first day of December in the first year of Yongxi, Song Taizong said to the Prime Minister, "It's very warm this winter ... it would be great if it snows three or five inches." . At that time, it didn't snow in summer calendar1February or even leap1February, indicating that winter was warm and lack of snow.

In addition, there are a lot of phenological data, which can also confirm the warm winter climate in most areas of the early and middle Northern Song Dynasty. Plum trees can only resist the lowest temperature of-14℃, so they can only survive in warm and humid conditions. During the Northern Song Dynasty, many kinds of plum trees were discovered in Tokyo, such as Hongmei and Jiang Mei. Mei Yao Chen, a poet in the Northern Song Dynasty, wrote a poem: "Only apricot stones are known here, and the girders also sell plum blossoms"; "When the messenger came back, the northerners first met Ren Yuemei"; "Remember in the old country, the horse wears bamboo incense. I will go by butterfly, and the trees will smell fragrant from the water. " [1] Zhu Bian, a poet in the Song Dynasty, once said: "It has flourished in recent years, but there are four kinds, namely, burnt calyx plum, green calyx plum and Chiba Huangxiangmei." [1] According to the geographical records of the Song Dynasty, the Imperial Garden in Tokyo and the later Long Live Mountain have "Meizhu" and "Meigang". Among them, Meigang "planted tens of thousands of plums, with green calyx bearing vines, fragrant and fragrant, with the structure of mountain roots, called' Sepals Green Flower Hall'", and its scale can be seen from this.