However, when the each year daily linear graphs are stacked on 
top of each other, the trend can be clearly identified (see Figure 
4). Figure 3 showed that the value of albedo for each day 
maybe fluctuated. However, the Figure 5 shows the pattern in 
which the value of albedo decreased and escalated at a 
consistent temporal trend and visually uniform each day for 10 
years. Though, the percentage of increment maybe different 
which results to some spikes of rises and falls as appeared in 
Figure 4. 
8 Days Time-Series Albedo 2000 - 2009 
2000 — 2001 1500000 2002 —— 2003 ov 2004 
m 2008 e 2006 verre 2027 2008 ne 2009 
Albedo 
  
1 17 33 42 65 B1 9/ 115129 145 161 L/; 193 209 225 24i 25/ 2/4 289 305 32: 337 333 
Day of Year 
  
  
  
Figure 4. Daily Albedo 2000 - 2009 (stacked line) 
3.2 Result 2: The Time-series Analyses (Yearly) 
The annual average minimum and maximum albedo of 
Peninsular Malaysia for years 2000-2009 is 0.002016594 and 
0.250059192 respectively. The temporal change trend lines of 
the study area present ascend trend (Figure 5). The highest 
albedo appears in the year 2006 and the lowest is in 2001. This 
change trend may be related to the land use types and the 
anthropogenic activities at the study area. Therefore, the 
companion analyses will focus on the monsoon variation. 
  
Yearly Average of Minimum and Maximum 
Albedo 
03 
du ho m Pe Raum m 
0.2 
0.25 
Albedo 
01 ~~ Minimum Average 
  
à maximum average 
0.05 
  
        
  
  
200n 200: 2002 2003 2004 2605 2066 32007 2008 200% 
  
Figure 5. Yearly Minimum and Maximum Average Albedo 
3.3 Result 3: The Time-series Analyses (Monsoon) 
Northeast Monsoon (Nov-Mar) is the wet season. Southwest 
Monsoon (May-Sept) is the drier season and Intermonsoon 
tends to experience extreme weather changes and the variation 
is more remarkable and intense. Traditionally, higher albedo 
results to a colder environment, and lower albedo makes 
temperature increased. Monsoon time-series shows albedo were 
acting differently due to the influence of daylight availability. 
Diffusion of skylight results to some reflectance values fail to 
be obtained by the sensor. Thus, the refectance value and 
monsoon behaviour show some disagreement with the common 
albedo-temperature behaviour (see para. Result 4). 
Figure 6 illustrates the variation of albedo in terms of the 
Malaysia's typical season. Day 281 until Day 329 shows some 
significant variation where spike can be identified and there is 
also an incremental movement of graph in between Day 121 to 
Day 145. These days are in the 2 intermediate Monsoons. 
Heavy rain and thunderstorm are common in these monsoons. 
The Southwest Monsoon represent drier season in Malaysia 
   
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
   
shows a reasonable variation (see Day 121 — 273). For year 
2001 until 2005, there is a steady period, where the albedo 
variation is somewhat stagnant. 
Monsoon Time-Series Albedo 2000 - 2009 
vn 200 MÁMIMr 9913 1053 os DGA CIDRE eexu$ c9 2D ces NA c 2008 
  
303 17 25 p: 4 ST 88 79 D 39 37 205 243 123 129 H7 L5 393131 289 277 285 193201 208 
Figure 6. Monsoon Albedo Variation 
353 13: 249 287 288 273 28: 232 237 305 313 321 322 337 345 353 331 
However, from year 2005 to 2009, the graph shows some rapid 
increased of albedo (see Day 121-145). A similar pattern of rise 
and fall value of albedo can be seen in Day 241 to Day 249. In 
Northeast Monsoon (wet season) which starts from Day 305 and 
fall back to March at Day 89 depict some extreme rise and fall 
which correspond to the nature of the season where heavy 
rainfall, variations of windspeed and it is a cold surges period 
especially at the east coast region of the study area. 
3.4 Result 4: Relationship with monthly Nebulosity Index 
and Aerosol Optical Depth (AOD) 
The correlation analyses for the nebulosity index and the aerosol 
optical depth is conducted in accordance to value represented in 
Table 2. By selecting month (Mar, Apr, Sept and Dec) 
according to the highest, mean and minimum value of 
nebulosity index as stated in (Zain-Ahmed et al. 2002). 
Nebulosity index indicates the sky that is at its less diffuse 
situation where usually representing less cloud (less diffuse, 
high index). Thus, these months are chosen to look for trend of 
albedo over the most clear, intermediate overcast and the most 
diffuse sky condition in Malaysia. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Months Neb AOD 
index 
Jan 0.55 0.2 
Feb 0.55 0.25 
Mar 0.56 0.25 
Apr 0.58 0.25 
May 0.47 0.25 
Jun 0.55 0.27 
July 0.54 0.32 
Aug 0.54 0.25 
Sept 0.52 0.43 
Oct 0.49 0.5 
Nov 0.45 0.25 
Dec 0.43 0.2 
  
  
  
  
Table 2. Monthly Nebulosity Index (Zain-Ahmed et al. 2002) 
and AOD (Kanniah and Yaso 2010) 
The monthly trend and the monsoon trend are influenced highly 
by the nebulosity index (see Figure 7). In correspondent to 
Figure 6, the increment and decline pattern in the graph can be 
conclude based on the value in Table 2. Although, December 
was classified as the wet and colder season, the albedo is 
relatively low compare to other month. This is due to the highly 
diffuse of skylight and being as the darkest month in a year. 
However, as the monsoon move to January, the albedo value is 
escalated as the nebulosity index is increased. Thus, Figure 7