During the night of March 31st, 2017, a severe precipitation event affected the city of Mocoa, in the tropical Andes. Total 24-h accumulated precipitation during that day was the fourth largest on record. Satellite data shows that the event was associated with a Mesoscale Convective System (MCS) that formed over the Amazon and moved westward, reaching the tropical Andes. Reanalysis data suggests that a rapid intensification of the Orinoco Low-Level Jet (OLLJ) traveling southwestward parallel to the Andes was a precursor that favored the zones of convergence for MCS formation. Upstream intensification of the OLLJ was evident 8 h prior to the Mocoa precipitation event. Given the lack of a dense network of observations in this understudied region, we use the Weather Research and Forecasting model (WRF) to explore the plausible mesoscale structures in the OLLJ region associated with the initiation and development of the MCS. We study an ensemble of simulations with different grid spacings (12, 4 and 1.3 km) and Planetary Boundary Layer (PBL) schemes (YSU, MYNN and QNSE). The more realistic MCSs were obtained with the QNSE and YSU schemes, given that the corresponding simulations included a density current in the lowest levels moving parallel to the Andes, with a sharp line of convergence and large vertical velocities over the leading edge of the mesoscale disturbance. In contrast, the MYNN scheme produced a weaker OLLJ and no density current. It is suggested that the stronger vertical mixing in the MYNN scheme was associated with the vertical dilution of the OLLJ, and with a much weaker low-level traveling perturbation via the upward radiation of energy by gravity waves. Our results help to better understand flood-producing extreme events over the poorly studied Andes-Amazon region and provide the groundwork for improved predictability of such storms.
机构:
Natl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R China
Pilot Natl Lab Marine Sci & Technol, Lab Reg Oceanog & Numer Modeling, Qingdao, Peoples R China
Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai, Peoples R China
Minist Nat Resources, Key Lab Marine Sci & Numer Modeling, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Luo, Yulan
Liu, Lin
论文数: 0引用数: 0
h-index: 0
机构:
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R China
Pilot Natl Lab Marine Sci & Technol, Lab Reg Oceanog & Numer Modeling, Qingdao, Peoples R China
Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai, Peoples R China
Minist Nat Resources, Key Lab Marine Sci & Numer Modeling, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Liu, Lin
Zhang, Yun
论文数: 0引用数: 0
h-index: 0
机构:
Natl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Zhang, Yun
Mehmood, Shahbaz
论文数: 0引用数: 0
h-index: 0
机构:
Minist Climate Change & Environm Coordinat MoCC&EC, Global Climate Change Impact Studies Ctr GCISC, Islamabad, PakistanNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Mehmood, Shahbaz
Yang, Yang
论文数: 0引用数: 0
h-index: 0
机构:
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R China
Minist Nat Resources, Key Lab Marine Sci & Numer Modeling, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Yang, Yang
Yang, Guang
论文数: 0引用数: 0
h-index: 0
机构:
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R China
Minist Nat Resources, Key Lab Marine Sci & Numer Modeling, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Yang, Guang
Duan, Yongliang
论文数: 0引用数: 0
h-index: 0
机构:
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R China
Minist Nat Resources, Key Lab Marine Sci & Numer Modeling, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Duan, Yongliang
Li, Qiuchi
论文数: 0引用数: 0
h-index: 0
机构:
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Li, Qiuchi
Zeng, Ai
论文数: 0引用数: 0
h-index: 0
机构:
Minist Nat Resources, Inst Oceanog 1, Qingdao, Peoples R China
Harbin Engn Univ, Qingdao, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
Zeng, Ai
Yu, Weidong
论文数: 0引用数: 0
h-index: 0
机构:
Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai, Peoples R China
Sun Yat Sen Univ, Zhuhai, Peoples R ChinaNatl Univ Def Technol, Coll Meteorol & Oceanog, Changsha, Peoples R China
机构:
Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Hunan, Peoples R China
Key Lab Water Sediment Sci & Water Disaster Preve, Changsha 410114, Hunan, Peoples R China
Univ Massachusetts Dartmouth, Sch Marine Sci & Technol, New Bedford, MA 02744 USA
Minist Water Resources, Key Lab Pearl River Estuarine Dynam & Associated, Guangzhou 510611, Guangdong, Peoples R ChinaChangsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Hunan, Peoples R China
Wu, Zhiyuan
Alshdaifat, Naire Mohamad
论文数: 0引用数: 0
h-index: 0
机构:
Univ Massachusetts Dartmouth, Coll Engn, Dartmouth, MA 02747 USAChangsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Hunan, Peoples R China