Details:

Journal Title:
Journal of Geophysical Research: Atmospheres
Personal Author:
Wei, Yuntao ; Pu, Zhaoxia ; Zhang, Chidong
Wei, Yuntao ; Pu, Zhaoxia ; Zhang, Chidong Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office) ; PMEL (Pacific Marine Environmental Laboratory)
OAR (Oceanic and Atmospheric Research) ; CPO (Climate Program Office) ; PMEL (Pacific Marine Environmental Laboratory) Less -
Description:
Cloud-permitting scale (3 km) simulations are made to investigate the diurnal cycle of precipitation (DCP) over the Indo-Pacific Maritime Continent under the modulation of the Madden-Julian Oscillation (MJO), focusing on January–February 2018 during the Years of the Maritime Continent (YMC). Comparisons with satellite precipitation and global reanalysis products show that the simulations reasonably capture main features of diurnal wind and precipitation. The MJO modulates the amplitude, timing, and propagation of the DCP through affecting both large-scale and local circulation and convection. Under local suppressed conditions, much strengthened sea/valley breezes are generally responsible for the enhanced and earlier-triggered (2- to 3-hr lead) DCP over land. Meanwhile, stronger cooling induced by enhanced stratiform rainfall excites well-developed gravity waves spreading outward and upward, accompanied by continuous decreases in low-level temperature and amplified land breezes, which cause stronger and further offshore-propagating DCP. The opposite is true under local active conditions. Modulated by the passing of MJO, the enhanced DCP also displays a systematic shift from the west to the east coasts of large islands, forming a unique dipolar structure in the anomalous island DCP. The DCP exhibits island-dependent characteristics: With topographical elevation, the triggering mechanism of island convection transforms from later penetrating sea breeze fronts over mountain foothills to early-excited valley winds over mountain tops. Steep topography also supports stronger intraseasonal variations of the DCP, which can be well explained by regional variations in land-sea/mountain-valley breezes, terrain lifting, and ambient wind-induced advective and vertical wind shear effects.
Keywords:
[+]
Cloud-permitting Simulation
Diurnal Cycle Of Precipitation
Madden-Julian Oscillation
Tropical Convection

Source:
Journal of Geophysical Research: Atmospheres, 125, e2020JD032529
DOI:
https://doi.org/10.1029/2020JD032529
Document Type:
Journal Article
Funding:
Grant no. NA17OAR4310262
Rights Information:
CC BY-NC
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:63991f1b2f2b25b242efbf6259d8244ecb353ad8e068f0941dd68d7c9137b74a
File Type:

Supporting Files

• No Additional Files

More +