近海水汽初值和对流影响一次华南前汛期沿海强降水对流系统发展过程的机理研究

鲁蓉; 孙建华; 傅慎明

doi:10.3878/j.issn.1006-9895.1705.16261

近海水汽初值和对流影响一次华南前汛期沿海强降水对流系统发展过程的机理研究

doi: 10.3878/j.issn.1006-9895.1705.16261

鲁蓉^{1, 2,},
孙建华^{1, 3, ,},
傅慎明¹

1.
中国科学院大气物理研究所, 北京 100029
2.
中国科学院大学, 北京 100049
3.
中国气象科学研究院灾害天气国家重点实验室, 北京 100081

基金项目:

国家自然科学基金项目 41675045

灾害天气国家重点实验室基金项目 2016LASW-B05

详细信息

作者简介:
鲁蓉, 女, 1990年出生, 博士研究生, 主要从事中尺度气象学研究。E-mail:lurongiap@sina.com

通讯作者:
孙建华, E-mail:sjh@mail.iap.ac.cn

中图分类号: P445
计量
- 文章访问数: 1987
- HTML全文浏览量: 59
- PDF下载量: 2008
- 被引次数: 0
出版历程
- 收稿日期: 2016-11-07
- 网络出版日期: 2017-05-16
- 刊出日期: 2018-01-15

Influence of Offshore Initial Moisture Field and Convection on the Development of Coastal Convection in a Heavy Rainfall Event over South China during the Pre-summer Rainy Season

Rong LU^{1, 2
,},
Jianhua SUN^{1, 3
, ,},
Shenming FU¹

1.
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029
2.
University of Chinese Academy of Sciences, Beijing 100049
3.
State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081

Funds:

National Natural Science Foundation of China 41675045

Fund of National Key Laboratory of Disaster Weather 2016LASW-B05

摘要

摘要: 本研究在对华南季风降水试验（SCMREX）观测资料分析的基础上，采用数值模拟试验探讨南海北部区域湿度场初值误差和海上对流对2014年5月8日华南沿海地区的一次强降雨过程的中尺度对流系统（MCS）的发展和移动的影响。加密探空和风廓线观测分析表明在珠江口地区有西南风和偏东风急流形成的辐合区，为对流在该地区增强发展提供了条件。增加和减少近海湿度以及关闭积云和微物理过程潜热释放，所造成的温度场以及风场的变化对广东沿海地区的对流的强度和移动路径都有明显的影响。特别是增加海上关键区的湿度，由于海上对流的发展改变了整个区域的环流，抑制了陆地上对流的发展。关闭海上关键区对流过程潜热的释放，导致低空急流到达更加偏北的位置，对流系统在模拟的后期向东北移动。通过这些试验表明，海上的湿度等要素场和对流活动对沿海地区的降雨预报有着十分重要的影响，需要进一步加强海上观测及其资料同化方法。
- 中尺度对流系统 /
- 低空急流 /
- 敏感试验 /
- 对流潜热 /
- 降雨预报
Abstract: This paper utilizes observation data from the SCMREX (Southern China Monsoon Rainfall Experiment) and numerical sensitive simulation experiments to investigate the influence of moisture amount and convection development over the northern South China Sea on MCS (Mesoscale Convective System) of a heavy rainfall event in coastal South China on May 8, 2014.Intensive soundings and wind profiler data reveal that there existed a convergence region formed by the southwesterly and easterly jet in the Pearl River delta, which provided a favorable condition for the development of convection.When the initial relative humidity was increased or decreased in the offshore area, or latent heat released from the cumulus and microphysical processes were turned off, significant effects could be found on the intensity and movement of convection in the coastal area of Guangdong owing to the adjustment of temperature and wind fields.In particular, when increasing offshore initial humidity, prosperous sea convection modified the circulation in the entire simulation area, and suppressed the development of convection over the land.Moreover, if latent heat from cumulus and microphysical processes were turned off, the low-level jet could reach further north, and the convective system moved to the northeast in the later stage.These experiments indicate that the offshore initial moisture field and convection are indeed important for precipitation forecast in the coastal area.Therefore it is necessary to enhance offshore observation and data assimilation method in the future.
- Mesoscale Convective System (MCS) /
- Low-level jets /
- Sensitivity experiment /
- Latent heat /
- Rainfall forecast

HTML全文

图 1 2014年5月8日（a）00时（协调世界时，下同）至9日00时24小时观测降雨量（单位：mm），以及（b）05、10、15、20时雷达组合反射率（单位：dBZ)。（a）图中蓝色和红色方块分别表示阳江和珠海观测站位置

Figure 1. (a) Observed accumulative precipitation from 0000 UTC 8 to 0000 UTC 9 May 2014 (units: mm) and (b) composite radar reflectivity at 0500 UTC, 1000 UTC, 1500 UTC, 2000 UTC 8 May (units: dBZ). The blue and red squares in figure (a) indicate the locations of Yangjiang and Zhuhai observation stations, respectively

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图 2 模拟区域图：（a）三重嵌套网格范围；（b）d03区域范围（阴影为华南地区地形高度，白色区域为所有敏感试验的海上关键区）

Figure 2. Schematic diagram of simulation domains: (a) Triple nesting domains; (b) d03 domain with shaded areas indicating South China terrain height and the white area indicating the critical offshore zone of all sensitive experiments

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图 3 2014年5月8日12时的环流形势：（a）500 hPa位势高度（黑色等值线，单位：dagpm）和整层可降水量（阴影，单位：mm）；(b) 850 hPa位势高度（黑色等值线，单位：dagpm）和风场（风标，风向杆全风速为4 m s^-1）以及对流有效位能（CAPE；阴影，单位：J kg^-1）

Figure 3. Synoptic weather pattern at 1200 UTC 8 May 2014: (a) Geopotential height (black isoline, units: dagpm) at 500 hPa and precipitable water (shaded, units: mm); (b) geopotential height (black isoline, units: dagpm), wind field (barbs, full bar represents wind speed of 4 m s^-1) at 850 hPa, and convective available potential energy (CAPE; shaded, units: J kg^-1)

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图 4 （a）2014年5月8日12时阳江站的T-logp图（黑色实线表示温度曲线，蓝色实线为露点温度曲线，单位：℃），（b）2014年5月7日18时至5月9日18时阳江站的探空风廓线（单位：m s^-1）

Figure 4. (a) Skew-T/logp diagram at Yangjiang station at 1200 UTC 8 May 2014 (the black line represents the temperature profile while the blue line represents the dew point profile, units: ℃), (b) wind profiles at Yangjiang station from 1800 UTC 7 May to 1800 UTC 9 May, 2014 (units: m s^-1)

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图 5 2014年5月8日00~23时珠海站的（a）风廓线（阴影为风速，单位: m s^-1）和（b）逐小时雨量分布（单位: mm）。横坐标（时间）从右向左

Figure 5. (a) Wind profiles (units: m s^-1) and (b) hourly rainfall (units: mm) at Zhuhai station on 8 May. The shadings in (a) represent wind speed, abscissa represents time (from right to left)

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图 6 2014年5月8日所有试验的模拟日降雨量（黑色实线，单位: mm）和观测的日降雨量（阴影，单位：mm）：（a）CNTL试验；（b）CLS试验；（c）RH90试验；（d）RH80试验；（e）RH110试验；（f）RH120试验

Figure 6. Comparisons of simulated daily precipitation (black solid lines, units: mm) for all experiments and observed daily precipitation (shaded, units: mm) on 8 May 2014: (a) CNTL experiment; (b) CLS experiment; (c) RH90 experiment; (d) RH80 experiment; (e) RH110 experiment; (f) RH120 experiment

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图 7 014年5月8日所有试验模拟的雷达组合反射率（阴影，单位：dBZ）、地面10 m风场（风标，大于8 m s^-1）以及小时雨量（蓝色等值线：间隔10 mm）：（a）CNTL试验；（b）RH90试验；（c）RH80试验；（d）RH110试验；（e）RH120试验；（f）CLS试验

Figure 7. Composite radar reflectivity (shaded, units: dBZ), hourly rainfall (blue lines, interval: 10 mm), and surface wind at 10 m (barbs, > 8m s^-1) simulated by all experiments on 8 May 2014 : (a) CNTL; (b) RH90; (c) RH80; (d) RH110; (e) RH120; (f) CLS

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图 8 5月8日07时对照试验与RH90（左列）、RH80（右列）试验的（a、b）925 hPa及（c、d）850 hPa温度场（阴影，单位：℃）、风场（风标，单位：m s^-1）差值。紫色等值线表示RH90、RH80试验与对照试验散度差负值（间隔3×10^-5 s^-1）

Figure 8. Differences (CNTL－RH90/80) in temperature (shaded, units: ℃) and wind (barbs, units: m s^-1) between CNTL and RH90 (RH80) experiments at 0700 UTC 8 May. Left panel represents RH90, and right panel represents RH80. Top and bottom panels are for (a, b) 925 hPa and (c, d) 850 hPa, respectively. Purple contours represent the convergence regions of RH90 and RH80 experiments relative to that of the control experiment (intervals: 3×10^-5 s^-1)

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图 9 5月8日07时对照试验与RH110（左列）、RH120（右列）试验的（a、b）925 hPa及（c、d）400 hPa温度场（阴影，单位：℃）和风场（风标，单位：m s^-1）差值，925 hPa紫色等值线同图 8，表示敏感试验相对于对照试验的辐合区，400 hPa则为对应的辐散区

Figure 9. Differences (CNTL－RH110/120) in temperature (shaded, units: ℃) and wind (barbs, units: m s^-1) between CNTL and RH110 (RH120) experiments at 0700 UTC 8 May. Left panel represents RH90, and right panel represents RH80. The top and bottom panels depict results at (a, b) 925 hPa and (c, d) 400 hPa, respectively. Purple contours at 925 hPa are the same as in Fig. 8, while those at 400 hPa represent divergence regions

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图 10 5月8日09时对照试验与CLS试验的温度（阴影，单位：℃）、风场（风标，单位：m s^-1）差值以及对照试验与CLS试验差值的相对辐合区（等值线，等值线间隔：3×10^-5 s^-1）：（a）925 hPa；（b）500 hPa。模拟的SLP（阴影，单位：hPa），CNTL－CLS试验SLP之差（等值线, 单位: hPa）：（c）8日09时, 叠加CLS试验SLP；（d）8日16时，叠加CNTL试验SLP

Figure 10. Differences (CNTL－CLS) in temperature (shaded, units: ℃), wind (barbs, units: m s^-1) between CNTL and CLS experiments and convergence regions of CLS relative to CNTL experiment (contours, intervals: 3×10^-5 s^-1) at 0900 UTC 8 May: (a) 925 hPa; (b) 500 hPa. SLP (shaded, units: hPa) and SLP differences between CLS and CNTL (CNTL－CLS, contours, units: hPa): (c) 0900 UTC 8 May (shaded areas indicate SLP in CLS); (d) 1600 UTC 8 May (shaded areas indicate SLP in CNTL)

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图 11 近海湿度初值场和对流影响陆地和海岸对流过程示意图

Figure 11. Schematic diagram of how offshore initial moisture field and convection influence the development of land and coastal convection

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表 1 试验方案

Table 1. Configuration of the numerical experiments

试验名称	试验方案
CNTL	对照试验
RH90	海上关键区内初始场水汽整层降低10%
RH80	海上关键区内初始场水汽整层降低20%
RH110	海上关键区内初始场水汽整层增加10%
RH120	海上关键区内初始场水汽整层增加20%
CLS	关闭海上关键区内积云与微物理过程潜热和感热释放

下载: 导出CSV

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