Search

Clutter removal of marine radar for weather observation depends on the quality and consistency of clutter map. the clutter removal often become difficult since echoes from hard targets are much stronger than the rain reflection. There is also constraint due to different azimuth angle of each scan line in every scanner rotation resulting inconsistent map of clutter. The effort to obtain consistent clutter map to easily distinguish the rain echoes depends on the method of signal pre-processing and pulse integration. Oversampling factor influences the target detection result as higher value enable the radar to see large object more detail. The type of LPF determines the clarity of the radar image, thus better clutter map. While the pulse integration improves probability of detection and produces better clutter removal when the radar is applied for rain observation since it can provide much stable static clutter map. [ABSTRACT FROM AUTHOR]

GSMaP and TRMM data validation was carried out with rainfall data in West Borneo. This study aims to evaluate the performance of GSMAP and TRMM in estimating daily rainfall in seven watersheds, namely Ambawang (AB), Kakap (KP), Pontianak (PT), Rasar (RS), Mandor (MD), Sebadu (SB), and Segedong. (SG). The analysis was performed using statistical analysis, error calculation, and rain event presentation. The results of the GSMaP satellite data validation against the observation data showed very high correlation values in all observation locations (R> 0.75). The similar result is also found in the TRMM data. In general, all of locations show a very small RMSE value. This indicates that the GSMaP and TRMM data tend to have a good performance in estimating rainfall in West Borneo. The relative bias values show pretty good results (<15%) except for MD both GSMaP and TRMM data. The results of the estimation of rainfall data show a tendency that GSMaP is overestimated compared to TRMM data in AB, KP, PT, RS, SB, and SG while TRMM is more representative of the actual conditions. Both GSMaP and TRMM data tend not to be able to detect rains smaller than 1 mm. Overall, the three rainfall data indicate that the percentage of the frequency of rainfall events based on six rainfall classifications in all observation locations often occurs at rainfall values of 1-10 mm. [ABSTRACT FROM AUTHOR]

This research conducted an experiment on EAR-RASS acoustic chirp signal to find the better configuration for virtual temperature profile data retrieval. A single frequency acoustic pulses are susceptible to Doppler shift error, the utilization of continuous wave and chirped signals become a solution. Therefore, commonly the acoustic wave source is transmitted at different frequencies in order to meet wavelength condition for obtaining Bragg condition at wide range of altitudes. Several chirp configurations for EAR-RASS have been tested by changing their sweep range and time during these experiments. The ray-tracing method is applied before each experiment and confirmed by the Doppler spectra performance to ensure that the observation is conducted in the RASS echoes region. Compared to the other configuration, the 90-110 Hz has better performance as it produces highest echo power hence better virtual temperature data retrieval. [ABSTRACT FROM AUTHOR]

LAPAN Transportable X-Band Weather Radar is an X-Band GMWR-25-SP single polarization weather radar. Field campaign were conducted from end of February until end of May 2017 in Bandung Basin urban area. The purpose of this research is to analyze the strong wind during severe storm (case study March 17) based on wind shear data. This strong wind are conform by the AWS ground based wind measurement from 11.00 LT until 12.00 LT with wind speed value varied from 4.5 - 12 m/s. A post processing using 2 dimensional (2D) combined shear method from the wind shear weather radar data were used to analyze the larger shear resulted from strong wind. 2D combined shear showed that local heavy storm generates from center location of Bandung from 10.50 LT then grew until 11.10 LT. Changes echo shape occur in 11.20 LT forming a v shape area with large value were spotted in the edge of the object, while varied color inside the v shape area showed a fluctuated wind shear that is also correlated with spectrum width value with more than 4 m/s. Based on the combined shear data in 11.30 LT, all of the impacted location recorded were located inside the wind shear area with two location were spotted having a large combined shear value reaching > 0.01 s-1. [ABSTRACT FROM AUTHOR]