Design and development of LIDAR systems for Atmospheric profiling, Atmospheric Aerosols and clouds, Indian Monsoon dynamics using wind profiler observations, Anomalous wave propagation in the atmopshere
M. Roja Raman, W.N. Chen (2014), Trends in monthly tropopause characteristics observed over Taipei, Taiwan, J. Atmos. Sci., 71, 4, 1323-1338.
Wei-Nai Chen, Yu-Chieh Chen, Chung-Yih Kuo, Chun-Hung Chou, Chung-Hao Cheng, Chun-Chieh Huang , Shih-Yu Chang⁎, M. Roja Raman, Wen-Lin Shang, Tzu-Yao Chuang , Su-Ching Liu (2014) . The real-time method of assessing the contribution of individual sources on visibility degradation in Taichung. Sci. Tot. Env., 497-498, 219-228.
Manjula. G., M. Roja Raman, M. Venkat Ratnam, A.V. Chandra Sekhar and S. Vijaya Bhaskara Rao (2016). Diurnal variation of ducts observed over a tropical station, Gadanki, using high-resolution GPS radiosonde observations. Radio Science, 51, 247-258, DOI:10.1002/2015RS005814.
Roja Raman, Wei-Nai Chen, Sin-Jie He, Li-Ting Chen, Kai-Hsuan Hsu, Jan-Bai Nee (2016). Investigation on the interlink between optical properties of dusts over Taiwan and Thar Desert, India using CALIPSO data. The European Physical Journal Conferences, 119, 04005, DOI: 10.1051/epjconf/201611904005.
Wei-Nai Chen, Yung-Chang Chen, Hui-Ming Hung, M. Roja Raman (2018). Investigating the effect of hygroscopicity of Aerosols on optical profiles of PBL observed by Dual- Wavelength Lidar. The European Physical Journal Conferences, 176, 05059 https://doi.org/10.1051/epjconf/201817605059.
M. Venkat Ratnam, P. Prasad, M. Roja Raman, V. Ravikiran, S. Vijaya Bhaskara Rao, B.V. Krishna Murthy, A. Jayaraman (2018). Role of dynamics on the formation and maintenance of the elevated aerosol layer during monsoon season over south-east peninsular India, Atmospheric Environment, 188, pp43-48.
P. Prasad, M. Roja Raman*, M. Venkat Ratnam, Wei-Nai Chen, S. Vijaya Bhaskara Rao, Mukunda M Gogoi, Sobhan Kumar Kompalli, S. Suresh Babu and K. Sarat Kumar (2018) Characterization of atmospheric Black Carbon over a semi-urban site of southeast India: Local sources and long-range transport, Atmospheric Research, 213, pp411-421.
A.Narendra Babu, V. Naveen Kumar, P. S. Brahmanandam, M. Purnachandra Rao, M. Roja Raman, K. Sreedhar (2018), Anomalous wind circulation over Taipei, Taiwan during the northern winter seasons of 2004 and 2005- A case study, Satellite Oceanography and Meteorology, Vol.3, Issue.2.
Prasad, P., Raman, M. R., Ratnam, M. V., Ravikiran, V., Madhavan, B. L., & Bhaskara Rao, S. V. (2019). Nocturnal, seasonal and intra-annual variability of tropospheric aerosols observed using ground-based and space-borne lidars over a tropical location of India. Atmospheric Environment, 213, 185–198.
V Ravikiran, M Venkat Ratnam, B V KRISHNA MURTHY, Yogesh Kant, Prasad P, Rojaraman Mekalathur, SVB Rao, Lakshmi Kumar TV, Animesh Maitra (2019), An empirical method for source apportionment of black carbon aerosol: Results from Aethalometer observations at five different locations in India, Environmental Pollution, 254-A, 112932.
Doppler wind lidar observations of boundary layer over Central Taiwan The first time observations of variability in atmospheric boundary layer structure and dynamics using continuous Doppler lidar observation over Taichung, a central Taiwan station is carried out. The vertical velocity variance (sw2) profiles and the Signal to Noise Ratio (SNR) of vertical beam pointing in the lower troposphere are used to identify the convective boundary layer (CBL) and the nocturnal boundary layer (NBL) separately with slightly different threshold conditions. The planetary boundary layer over Taichung is found to be as shallow as 150m during late night and early morning hours and as high as 1500m during mid-day hours. Due to the interlock between the wide coastal belt in the west and extensive mountain range in the east, the boundary layer shows complex dynamical properties with double layered structures of opposite wind flows most of the time. Reference: . MRRaman and WNChen, 2019, ILRC.
Development of DIAL lidar for tropospheric Ozone profiling The project is aimed to develop a portable DIAL Lidar system for tropospheric ozone profiling. Though this technique is not new, we are trying to redesign the system for more efficient SRS conversion of the on and off ozone absorption wavelengths and looking for the alternative latest available technologies for the wide spectrum reception to make use of same system for ozone as well as SO2 measurements simultaneously. Unlike other existing systems, we are using to use Hydrogen and Methane with Argon and Helium as buffer gas for efficient conversion of 266nm excited to 288 and 299nm. The conversion efficiency of 266 SRS with multiple pressure, gas and laser energy combinations is being tested.