Meteorological Modeling In Klang Valley Region Malaysia Environmental Sciences Essay
It has been widely known that alterations of the land surface from flora country to urban country can well impact the environing meteoric status. Meteorologic theoretical account was used to measure meteoric status for air quality mold and prediction. One of the inputs for the meteoric and air quality theoretical account is land usage and land screen of the terrain. In this survey, we examined the sensitiveness of land usage and land screen on the predicted meteoric conditions. A meteoric simulation utilizing 5th coevals mesoscale theoretical account ( MM5 ) by Penn State/NCAR was used to compare the effects of land usage from two different old ages on meteoric status. The predicted meteoric conditions are so compared with the several monitoring station onsite. Consequences showed improved of surface wind velocity and temperature simulated utilizing improved land usage map. Findingss suggest land usage map should be taking into consideration in historical meteoric Fieldss to entree future air quality if the country of survey expects big alterations in land usage form.
Keywords: Meteorologic mold ; Land usage ; MM5 ; Urban.
It has been widely known that alterations of the land surface from flora country to urban country can well impact the environing meteoric status. Urbanization of an country could take to alterations of meteoric parametric quantities such as boundary bed deepness, perpendicular diffusivity, wind stableness category, etc. These meteoric parametric quantities played an of import function in most of the air quality theoretical accounts that predicts the concentration at each grid. Harmonizing to Jacobson ( 2002 ) , one of the factors that affect air pollution is the local air current which ensuing from uneven land warming, variable topography and others. In another word, different land usage type may take to uneven land warming, because land screen affects ground temperature, which affects pollutant concentration finally ( Jacobson, 2002 ) . Meteorologic and air quality theoretical accounts require land usage and surface feature that differ by their land usage and land screen forms ( Civerolo et. at. , 2000 ) . Another survey carried out by Jazcilevich et Al. ( 2002 ) suggested that alterations of the land usage type could impact its environing meteoric status and scattering of air pollutant. Much of the current apprehension of the urban clime and meteoric status in Malaysia resulted from the research on Kuala Lumpur and Petaling Jaya country begins from 1970s ( Sham, 1973a, 1973b, 1979a, 1979b and 1987 ) . These researches focused on the description of the climatology and meteoric facet such as air current and temperature parametric quantities associated with urban heat island. The meteoric facets of the Kuala Lumpur and the environing metropoliss may alter due to the change of land usage and land screen by urbanisation and development of the metropolis. However, no survey had been done to entree the meteoric status of Klang Valley part with current land usage and land screen.
The meteoric theoretical account used in this survey was the Fifth Generation Mesoscale Model ( MM5 ) from PSU/NCAR ( Grell et al. , 1994 ) . In this theoretical account the land usage was simulated from the planetary flora dataset from USGS which available at 1 grade, 30 min, 10 min, 5 min, and 30 unsweet declaration. However, the informations were derived from satellite observations over a period 1992-3 and the flora classs were out of day of the month and non relevant to the country of survey. The aim of the survey is to find to the effects of the land usage and land screen alterations on the meteoric mold system. Land usage map of twelvemonth 2000 obtain from the Town and Country Planning Department ( JPBD ) will be used to better 1992-3 USGS land usage dataset.
The Modeling System
PSU/NCAR Fifth Generation Mesoscale Model ( MM5 ) was selected as the meteoric simulation patterning system in this survey. The MM5 theoretical account is non-hydrostatic with terrain following co-ordinates, multi-scale, capable of interface with existent conditions prognosis theoretical accounts ( Global Circulation Model ) , contains expressed cloud strategies and dirt parameterization. MM5 is widely used by the meteoric community and its end product could be coupled together with the Sparse Matrix Operation Kernel Emission ( SMOKE ) theoretical account and Community Multiscale Air Quality ( CMAQ ) theoretical account to imitate the scattering of the air pollutants that take in considerations of the meteoric Fieldss and emanation beginnings. MRF Planetary Boundary Layer ( PBL ) parameterization strategy was selected in this survey. The 4-dimensional informations assimilation ( FDDA ) option was non used was selected in this survey because the purpose of the survey is to analyze the effects of modified land usage on the theoretical account end product. For inputs of informations, land usage datasets from USGS will be used as the default land usage, and land usage map from Town and Country Planning Department as the improved land usage and NCEP FNL ( Final ) Operational Global Analysis information was used in this survey.
Four spheres are used as shown in Figure 1 for this survey. The female parent sphere with the declaration 27km covers the most of the Peninsular Malaysia ; 2nd sphere with the 9km declaration screens Selangor province ; 3rd sphere with 3km declaration screens ; finest sphere with 1km declaration will covers the survey country which is Klang Valley.
Figure 1: MM5 domain apparatus.
Processing of Land Use and Land Cover
In the MM5 mold system, each grid cell was assigned one land usage based on the dominant class in the grid cell. 24 classs of Vegetation type by USGS was used in categorization of land usage in MM5. Each land usage categories consists of six surface parameterization, which includes, reflective power, wet handiness, emissitivity at 9 Aµm, raggedness length, thermic inactiveness, and surface heat capacity per unit volume giving together with the MM5 theoretical account. Since Malaysia is a tropical state, summertime values are used. Out of 24 land usage types in the MM5 theoretical account ( Guo and Chen, 1994 ) , 14 classs was used to to the full depict the full sphere ( Figure 2 ) , with 22 % classified as H2O organic structures, 0.4 % as urban country and the largest non water-based class is Irrigated Cropland and Pasture ( 39 % ) in sphere 3 and as for sphere 4, 10 % classified as H2O organic structures, 1 % as urban country and the largest non water-based class besides class is Irrigated Cropland and Pasture ( 37 % ) ( Table 1 ) .
Figure 2: USGS land usage dataset sphere 3 and domain 4.
Since the Land usage dataset from USGS was generated from the twelvemonth 1992/3 orbiter image, the development of the Klang Valley country for the past 15 old ages decidedly changed the land usage and land screen of the survey country. To better the land usage type, updated land usage map from the Town and Country Planning Department was referred in this survey. The updated land usage map was preprocessed from polygon to gridded land usage map based on the categorization of the 24 USGS land usage classs ( Figure 3 ) .The per centum differences of the land usage between the default land usage and the update land usage are shown in ( Table 1 ) .
Table 1: Percentage of landuse class for USGS and JPBD land usage Domain 3 and Domain 4.
Land usage codification
Land usage class
Land usage Domain 3 ( % )
Land usage Domain 4 ( % )
Land usage Domain 3 ( % )
Land usage Domain 4 ( % )
Urban and Built -Up Area
Dryland Cropland and Pasture
Irrigated Cropland and Pasture
Mixed Dryland/Irrigated Cropland and Pasture
Deciduous Broadleaf Forest
Evergreen Broadleaf Forest
Evergreen Needleleaf Forest
Figure 3: Gridded JPBD land usage in 3km and 1km declaration.
An ASCII type of input file was generated based on the reclassified land usage map into specific format. This ASCII file contains column, row, land usage type, latitude, longitude, flora fraction, and H2O fraction ( Figure 4 ) .
Figure 4: Example of ASCII format input.
The FORTRAN codification named “ replace_lulc.f ” is used to replace the land usage type, flora fraction and H2O fraction in the TERRAIN_DOMAINx file based on the co-ordinates of the reclassified grid cells and the several land usage type, and other parametric quantities provided in the ASCII file. The FORTRAN codification is compiled utilizing run book “ run.replace ” which besides determines the input and end product files to treat, and parametric quantities to be updated ( Figure 5 ) .
Figure 5: Example of run.replace book.
MM5 Simulation Results
MM5 simulation was performed from 1st July 2005 ( 18:00 ) to 3rd July 2005 ( 17:00 ) with entire simulation clip 48 hours utilizing USGS flora dataset for 27km, 9km, 3km and 1km spheres as base instance. The 3km and 1km sphere will be compared with the end product of MM5 simulation using JPBD land usage dataset during for same period. All the physical options used were indistinguishable for both simulations. Observation from the Continuous Air Quality Monitoring ( CAQM ) station from Alam Sekitar Malaysia Sdn. Bhd. ( ASMA ) and Malayan Meteorological Department ( MMD ) was used to formalize MM5 public presentation from the both USGS and improved land usage dataset. Three CAQM site was selected to formalize the MM5 public presentation, which are the monitoring station in Klang and Shah Alam that maintained by ASMA and supervising station in Subang that operated by MMD.
The simulations that utilized USGS land usage dataset showed overestimate of the air current velocity and produces sudden extremum at certain hr in the simulation. The improved land usage dataset utilizing JPBD land usage informations reduces the air current velocity and frequence of the sudden extremum, yet still over estimated the overall air current velocity compared to the observation informations ( Figure 6 ) . However, the improved land usage dataset utilizing JPBD do increase the correlativity between the ascertained air current velocity and simulated air currents velocity from all CAQM site ( Table 2 ) . The lowered air current velocity due to the improved land usage informations set could take to increased stableness and decreased perpendicular commixture. This could increase the air pollution concentration in certain country.
The temperature profile simulated by both utilizing USGS and JPBD land usage dataset able to imitate the afternoon temperature near surface when comparison with the onsite observation temperature informations. However, both USGS and JPBD land usage dataset tends to overrate the temperature near surface during the dark ( Figure 7 ) . The correlativity between ascertained temperature and fake temperature somewhat increases when use JPBD land usage dataset in the simulation for the all monitoring site ( Table 2 ) .
The consequences suggest that improved land usage dataset utilizing JPBD land usage dataset could better the overall simulation consequence ( Table 2 ) . The alterations of the meteoric parametric quantities could impact scattering of air pollutant, energy demand that could impact anthropogenetic emanations. The alterations of the MM5 end product could besides impact the computation of the air pollution patterning package such as CMAQ.
Figure 6: Time series comparing of windspeed at 1km sphere for Shah Alam.
Figure 7: Time series comparing of 1.5m temperature at 1km sphere for Shah Alam.
Figure 8: Correlation between observed and predicted informations at Shah Alam.
Table 2: Summary of correlativity between observed and predicted informations for all the location.
Shah Alam, ASMA
Wind speed 10m
Domain 3 USGS
Domain 3 JPBD
Domain 4 USGS
Domain 4 JPBD
Domain 3 USGS
Domain 3 JPBD
Domain 4 USGS
Domain 4 JPBD
The land usage is merely one of many factors that take in consideration by the meteoric mold system. The consequences showed betterment of the fake air current velocity and temperature near surface. The public presentation of the MM5 on simulation could be improved by modifying the MM5 physical options and strategies depending on the declaration and location of the survey country. Since the land usage and land screen alterations affects the close surface meteorological, it should be included as one of the cardinal factors in the air pollution patterning particularly future air quality scenario. The alterations of the temperature that lead by land usage could increase downwind, and potentially affects the air quality simulation. The alterations of the air current velocity besides affect the dispersion of air pollutants and blending in the ambiance, alterations of the air pollutant concentration are expected.
Changing in the land usage and land screen forms due to the urban conurbation, altering of agricultural forms, forestation and deforestation are expected to affects to landscape. The change of landscape will take to alterations in population, energy ingestion, anthropogenetic and biogenic emanations. The consequences suggested that land usage should be taken into consideration when utilizing air quality calculating theoretical account to predicts and measure the air quality.
The writers thank the Ministry of Science and Technology ( MOSTI ) Malaysia for back uping this research, under undertaking no. 04-01-04-SF0674. We besides thank Department of Environment ( DOE ) Malaysia, Malaysian Meteorological Department ( MMD ) and Town and Planning Department ( JPBD ) Malaysia for informations providing. The Positions expressed by the authours do non neccesarily reflect those of the bureau.