晚霜茶园下垫面气温变化动态
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摘要
早春晚霜冻害对早熟名优茶生产造成严重危害,为探索茶园防霜方法与技术,研究了晚霜时茶园下垫面气温的变化特点。在分析茶园小气候和晚霜形成的基础上,试验测定茶树冠层上方12 m高度范围内的气温,分析其时空分布特征,以及不同天气条件对成霜的影响。结果表明:在早春晴朗、风速小于0.5 m·s-1的夜晚,当气温降至0℃时,易随辐射逆温的出现而成霜,风速大于2.0 m·s-1或阴雨天时则无霜;逆温约始于傍晚17:30,之后逆温强度迅速增大,最大的逆温差为9.9℃;从20:00至第2日06:00逆温强度波动较平稳,平均波动率为14.1%,其后逆温强度迅速减弱,在8:00左右逆温基本消失;在1:00~6:00时段,近地气温在高度方向上分层显著,(0~3.0),(6.0~7.5)m高度范围的温升变化率较大,分别为1.51℃·m-1和1.58℃·m-1,而(3.0~6.0),(7.5~12.0)m高度范围的温升变化不明显,故6.0~7.5 m可作为防霜风机优选的安装高度。
During early spring,early-maturing superior tea tends to suffer severe late frost damage. Temperature variation of underlying surface of tea plantation was studied under late frost in order to develop frost protection methods and technologies. On the basis of analysis on the microclimate of tea fields and late frost occurrence,experiments were conducted to measure the air temperature within 12 m high above the tea canopy. The spatial-temporal distribution of air temperature and the influence of different weather conditions on frost occurrence were analyzed. The results showed that the radiation frost was prone to occur with thermal inversion during clear spring night when air temperature was around 0℃ and wind speed was less than 0. 5 m·s-1. But there was no frost during rainy or cloudy nights or when the wind speed was above 2. 0 m·s- 1. Thermal inversion appeared around 17: 30 and inversion intensity increased rapidly. The maximum inversion difference was up to 9. 9℃. The variation of inversion intensity was relatively stable during 20∶ 00- 6∶ 00 with the average volatility of 14. 1%. Then inversion intensity weakened sharply, and thermal inversion almost disappeared around 8: 00. Air temperature near ground was clearly stratified vertically. The temperature rising rate within 0- 3. 0 m and 6. 0- 7. 5 m high was 1. 51 and 1. 58 ℃·m- 1,which was greater, but was unremarkable within the height of 3. 0- 6. 0 m and 7. 5- 12. 0 m. Therefore,6. 0- 7. 5 m would be the optimal height for the installation of frost protection fans.
During early spring,early-maturing superior tea tends to suffer severe late frost damage. Temperature variation of underlying surface of tea plantation was studied under late frost in order to develop frost protection methods and technologies. On the basis of analysis on the microclimate of tea fields and late frost occurrence,experiments were conducted to measure the air temperature within 12 m high above the tea canopy. The spatial-temporal distribution of air temperature and the influence of different weather conditions on frost occurrence were analyzed. The results showed that the radiation frost was prone to occur with thermal inversion during clear spring night when air temperature was around 0℃ and wind speed was less than 0. 5 m·s-1. But there was no frost during rainy or cloudy nights or when the wind speed was above 2. 0 m·s- 1. Thermal inversion appeared around 17: 30 and inversion intensity increased rapidly. The maximum inversion difference was up to 9. 9℃. The variation of inversion intensity was relatively stable during 20∶ 00- 6∶ 00 with the average volatility of 14. 1%. Then inversion intensity weakened sharply, and thermal inversion almost disappeared around 8: 00. Air temperature near ground was clearly stratified vertically. The temperature rising rate within 0- 3. 0 m and 6. 0- 7. 5 m high was 1. 51 and 1. 58 ℃·m- 1,which was greater, but was unremarkable within the height of 3. 0- 6. 0 m and 7. 5- 12. 0 m. Therefore,6. 0- 7. 5 m would be the optimal height for the installation of frost protection fans.
引文
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[12]兰忠明,张辉,林新坚,等.高、中丘陵山坡地逆温效应研究[J].农业现代化研究,2008,29(5):633-636.
[13]兰忠明,张辉,蔡文华.山地丘陵坡地逆温效应对果树避冻的影响[J].山地学报,2009,27(2):188-194.
[14]龙志云.逆温霜冻条件下植物冠层数值模拟分析[D].杭州:浙江大学,2010.
[15]钟秀丽.近20年来霜冻害的发生与防御研究进展[J].中国农业气象,2003,24(1):4-6.
[16]张一平,刘洋.云南古茶园与常规茶园小气候特征比较研究[J].华南农业大学学报,2005,26(4):17-21.
[17]姜会飞.农业气象学[M].北京:科学出版社,2008.
[18]段献忠.珠江三角洲地区逆温的特征分析及数值模拟研究[D].广州:中山大学,2009.
[2]杨书运.茶树冻害防控方法的研究[D].合肥:安徽农业大学,2012.
[3]王春乙.中国重大农业气象灾害研究[M].北京:气象出版社,2010.
[4]Furuta M,Araki S.Frost prevention fan apparatus having automatic folding type neck mechanism[P].JP.JP2007000096.2007-01-11.
[5]Ribeiro AC,Melo-Abreu JP,Snyder RL.Apple orchard frost protection with wind machine operation[J].Agricultural and Forest Meteorology,2006,141(2-4):71-81.
[6]Snyder RL,Melo-Abreu JP.Frost protection:fundamentals,practice,and economics—Vol I[M].Rome:Food and Agriculture Organization of the United Nations,2005.
[7]Yazdanpanah H,Stigter CJ.Selective inverted sink efficiency for spring frost protection in almond orchards northwest of Isfahan,Iran[J].Theoretical and Applied Climatology,2011,105(1-2):27-35.
[8]Feldhake CM.Forage frost protection potential of conifer silvopastures[J].Agricultural and Forest Meteorology,2002,112(2):123-130.
[9]李萍萍,戴青玲,胡永光.早春逆温条件下茶园近地温度时空分布特征[J].生态与农业环境学报,2008,24(1):39-42.
[10]胡永光,李萍萍,戴青玲,等.茶园高架风扇防霜系统设计与试验[J].农业机械学报,2007,38(12):97-99.
[11]胡永光,张红,李萍萍.茶园气流扰动防霜控制探析[J].江苏农业科学,2012,40(11):398-400.
[12]兰忠明,张辉,林新坚,等.高、中丘陵山坡地逆温效应研究[J].农业现代化研究,2008,29(5):633-636.
[13]兰忠明,张辉,蔡文华.山地丘陵坡地逆温效应对果树避冻的影响[J].山地学报,2009,27(2):188-194.
[14]龙志云.逆温霜冻条件下植物冠层数值模拟分析[D].杭州:浙江大学,2010.
[15]钟秀丽.近20年来霜冻害的发生与防御研究进展[J].中国农业气象,2003,24(1):4-6.
[16]张一平,刘洋.云南古茶园与常规茶园小气候特征比较研究[J].华南农业大学学报,2005,26(4):17-21.
[17]姜会飞.农业气象学[M].北京:科学出版社,2008.
[18]段献忠.珠江三角洲地区逆温的特征分析及数值模拟研究[D].广州:中山大学,2009.