Improvement of MODIS land cover classification over the Asia-Oceania region

Park, Ji-Yeol; Suh, Myoung‐Seok

doi:10.7780/kjrs.2015.31.2.1

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…For the initial and boundary conditions of the model, we used the ERA5 data [24]. The land cover data used are 30-arc second data for the Asian region [25]. The topography data used in this study are the USGS 30-arc second data for domains 1 and 2 and the Shuttle Radar Topography Mission (SRTM) 3-arc second data [26] for domains 3 and 4, respectively.…”

Section: Modelmentioning

confidence: 99%

Planetary Boundary Layer Flow over Complex Terrain during a Cold Surge Event: A Case Study

Lee,

Lim,

Lee

2024

Atmosphere

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Planetary boundary layer (PBL) flow over complex terrain during a cold surge event was investigated using 3-hourly radiosonde measurements in upwind, near ridge, and downwind locations of mountains in the northeastern part of Republic of Korea and using a high-resolution (333-m) numerical simulation. A cold surge occurred on 23 January 2018 and lasted for 4 days. We analyzed onset day of the cold surge when air temperature dropped rapidly. Analysis of the radiosonde data shows that the PBL was characterized by an adiabatic layer with strong capping inversion in early morning and evening as well as during daytime in the upwind and near-ridge sites. The PBL flow at the near-ridge site was strongest among three sites except at 0600 local standard time (LST) when the PBL flow in the lee was strongest. We performed high-resolution (333-m) numerical simulations using the Weather Research and Forecasting (WRF) model. The adiabatic PBL in the upwind site at 0600 LST was simulated, although its depth was underestimated. The model reproduced the strong low-level wind at 0600 LST and large wind shear during the daytime in the lee, but it did not capture the exact timing of the large wind shear. The model showed overall good performance in simulating the vertical profile of the virtual potential temperature and wind below 2 km above ground level at the three sites, with a high index of agreement (IOA) except for the wind at 1200 and 1500 LST in the lee. To examine the cause for the different behavior of PBL flow in the lee of mountains between 0600 LST and the daytime, we calculated the Froude number for PBL flow using radiosonde measurements based on reduced gravity shallow water (RGSW) theory. At 0600 LST, the upwind Froude number F0 was close to 1, while during the daytime, it was much lower than 1. The observed lee flow behavior was consistent with the flow regime change of a single layer over an obstacle with changing F0; the flow with a propagating lee jump changes into that with a stationary lee jump with decreasing F0. Numerical simulation shows that the steepening of streamlines of lee-wave field leads to a jump-like structure in the lee of mountains during the daytime.

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Section: Modelmentioning

confidence: 99%

Planetary Boundary Layer Flow over Complex Terrain during a Cold Surge Event: A Case Study

Lee,

Lim,

Lee

2024

Atmosphere

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“…For the initial and boundary condition of the WRF model, we used the Global Data Assimilation System (GDAS) FNL data with a resolution of 0.25 • provided by the National Centers for Environmental Prediction/National Centers for Atmospheric Research (NCEP/NCAR). For the land cover data, 30-arc second data [25] were used in domains 1 and 2, and 3-arc second data for the SMA [26] were used in domain 3. For topography data, the USGS 30-arc second data were used for domains 1 and 2 and the Shuttle Radar Topography Mission (SRTM) 3-arc second data [27] were used for domains 3.…”

Section: Datamentioning

confidence: 99%

Urban Effect on Sea-Breeze-Initiated Rainfall: A Case Study for Seoul Metropolitan Area

Choi

Lee

2021

Atmosphere

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We examined the sea-breeze-initiated rainfall in the Seoul Metropolitan area (SMA) on 6 July 2017 using the weather research and forecasting (WRF) model. The model captures the arrival of the sea breeze front (SBF), the development of afternoon rainfall in the SMA, and the location of the sea-breeze-initiated maximum rainfall in the northeastern SMA reasonably well but overestimates the subsequent rainfall. We conducted sensitivity tests to better understand the urban effect on the sea-breeze-initiated rainfall event. Through factor separation analysis, we first examined the explicit role of sea and urban effect on sea-breeze-initiated rainfall. The results show that the interaction of sea and urban effects cause rainfall in the northwest and northeast of the SMA, indicating that both urban heat island circulation (UHIC) and sea breeze play an important role in the study case’s rainfall. We further examined the relative role of urban roughness and anthropogenic heat on the sea-breeze-initiated rainfall through factor separation analysis. Both anthropogenic heat and urban roughness play a role in increasing precipitation in the northeastern area of the SMA, with a larger contribution of anthropogenic heat than urban roughness. The relationship between low-level convergence at the SBF and urban factors is discussed.

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“…The SST data of 6 September 2014 were used during simulation period. The land cover data used were the Korean Peninsula 30-arc second data (Park and Suh 2015) and the Seoul Metropolitan area 3-arc second data (NIMR 2014).…”

Section: Model Setup and Datamentioning

confidence: 99%

Implementation of tidal parameterization in the Weather Research and Forecasting (WRF) model

Lee¹,

Ahn²,

Lee³

et al. 2020

Terr. Atmos. Ocean. Sci.

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In this study, the Noah land surface model with a tidal parameterization was implemented in the WRF model. Newly added inputs included gridded tidal data that indicated the presence of a tidal flat, and a time varying water layer thickness over the tidal flat. Two simulations were performed in an online mode, namely, a simulation without tidal effects (CNTL) and simulation with tidal effects (TIDE). A comparison between the simulations and observations at flux tower showed that the surface heat and momentum fluxes were well reproduced in the TIDE simulation both in the magnitude and variation. In spite of better surface flux simulations, the air temperatures were slightly better simulated in the TIDE simulation than in the CNTL simulation during nighttime only. The 10 m wind speed was slightly overestimated in the TIDE compared to the CNTL simulation. The mean differences in the field variables between the TIDE and CNTL simulations were examined for four cases during the simulation period (inundation and exposed conditions at night and inundation and exposed conditions during the day). Tidal grids were classified into two groups depending on the land use type in the CNTL simulation as either the land to tide (LT) group or the water to tide (WT) group. The magnitude of the 2 m air temperature difference between the two simulations was generally larger on LT group than on WT group. During the day, both the 2 m air temperature and the planetary boundary layer height (PBLH) decreased under inundation conditions over LT group. The impact of the tidal flat on 10 m wind and PBLH extended inland beyond the tidal flats during the daytime inundation period.

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Improvement of MODIS land cover classification over the Asia-Oceania region

Cited by 6 publications

References 18 publications

Planetary Boundary Layer Flow over Complex Terrain during a Cold Surge Event: A Case Study

Planetary Boundary Layer Flow over Complex Terrain during a Cold Surge Event: A Case Study

Urban Effect on Sea-Breeze-Initiated Rainfall: A Case Study for Seoul Metropolitan Area

Implementation of tidal parameterization in the Weather Research and Forecasting (WRF) model

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