Science is for Sharing

Our long awaited publication exploring the Descending Cirrus clouds over Gadanki. Int'l. Journal of Remote Sensing It is the story of Cirrus clouds which descends / ascends altitude ..... their characteristic properties ....using NARL's long term Lidar data. Nellore Manoj Kumar, Kannan Venkatramanan, Anish Kumar M. Nair & Shekatam Satheesh Kumar   (2020)   On the characterization of descending nature of cirrus clouds over a tropical site, Gadanki,   International Journal of Remote Sensing,   41:17,   6550-6569,   DOI:  10.1080/01431161.2020.1742942 https://t.co/vpReYZZZsY https://t.co/3zJDq2KNjM https://www.tandfonline.com/doi/abs/10.1080/01431161.2020.1742942 The interesting feature of Cirrus cloud's descending & ascending are well characterized using ~6 years of lidar observations. The study roots back to the inspiration from my earlier work published in J.Geophysicsl Research in 2012 Nair,  A. K. M.   ,  K....

Our collaborative research article Sensitivity of climate models in relation to the “pool of inhibited cloudiness” over South of the Bay of Bengal  is published in the International Journal of Climatology recently. [ click to view the paper ] / [ click here to download the paper ] It is on evaluation of CMIP5 models and suites of CFSv2 in capturing a region known as "Pool of inhibited cloudiness" [ click to view the base paper ] over the southwest Bay of Bengal region. This region was actually identified based on satellite observation by Nair et al. (2011)   However, the fidelity of climate models were not evaluated to capture this region of suppressed convection (surrounded by region of deep convection). Climate models (cmip5 and CFSv2 default) shows difficulties in simulating the region. However, improved cloud physics seem to have played an important role in capturing the complex process Present Paper: Roy, K., Mukhopadhyay, P., Mu...

🌞Eclipses 🌚  are heavenly visual feasts of celestial bodies hide and seek game with light and shadow. Indeed, they are rare events ! We need to be in the right place 🗺 and at right time  ⌚ to watch an eclipse unfurl. 💥How about watching a future eclipse now ? Yes, it is possible !   Curious to know ? 🤔 We can simulate it in our PC 💻 and enjoy. No need to travel far off. It would be truly interesting to watch it in advance and later wait at the right place to witness it. ❓ How to simulate a heavenly event ? Use the free open source Astronomy software  "Stellarium"  - to enjoy the realistic sky.⭐🌟⋆ It can be downloaded at  https://stellarium.org/ Set the location (latitude, longitude), change the time, play and watch !!! This would be really interesting and rewarding activity.  Now, let us see how an  Annular Solar Eclipse of  26 December 2019  📅 look like. An Annular Solar Eclipse...

Our paper published in the Atmospheric Science Letters on different types of clouds during monsoon phases. The study was mainly carried out using Ka-band doppler weather radar of IITM. https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/asl.847 Chakravarty, K., Pokhrel, S., Kalshetti, M., Nair, A. K. M., Kalapureddy, M. C. R., Deshpande, S. M., … Goswami, B. N. (2018). Unraveling of cloud types during phases of monsoon intra-seasonal oscillations by a Ka-band Doppler weather radar. Atmospheric Science Letters , 19 (9), e847. http://doi.org/10.1002/asl.847 https://doi.org/10.1002/asl.847

Our article "Enhanced daytime occurrence of clouds in the tropical upper troposphere over land and ocean" published in Atmospheric Research  Gupta, A. K., Rajeev, K., Sijikumar, S., & Nair, A. K. M. (2018). Enhanced daytime occurrence of clouds in the tropical upper troposphere over land and ocean. Atmospheric Research , 201 (October 2017), 133–143. http://doi.org/10.1016/j.atmosres.2017.10.018 https://www.sciencedirect.com/science/article/pii/S0169809517302235

Our latest paper on the "Role of cloud feedback in regulating the “pool of inhibited cloudiness” over the Bay of Bengal" published in Springer Nature's  Meteorology and Atmospheric Physics . https://goo.gl/bNdLFg Read & Share Full Article here: http://rdcu.be/wOmz Anish Kumar M. Nair,  T. N. Rao and  K. Rajeev   Reference .bib   @Article{nair2017,   author   = {Nair, Anish Kumar M. and Rao, T. Narayana and Rajeev, K.},   title    = {Role of cloud feedback in regulating the “pool of inhibited cloudiness” over the Bay of Bengal},   journal  = {Meteorology and Atmospheric Physics},   year     = {2017},   pages    = {1--12},   month    = {10},   issn     = {0177-7971},   abstract = {Cloud-circulation feedback by latent heating (LH) is a major contributor for driving atmospheric circulation. This study exami...

Congrats Dr. Suresh Babu for bagging the prestigious Shanthi Swarup Bhatnagar Prize 2017. CLICK HERE  Proud of you...!!! Wishing you and team more success !!

An Equinox is the astronomical event when both the hemispheres have equal duration and amount of sunshine. Sun would be exactly overhead of the equator. It happens twice in a year Spring (Summer) equinox (20 March) and Vernal (Autumnal) equinox (22 September) . Here is the view of the beautiful event from space for 22 September 2016. I have animated it (time series for the day). Watch the day-night solar terminator move through the earth. Observe the equal area of sunshine and night on either hemisphere. The visible imagery is from MeteoSat VISSR (IODC) stationed at 57deg.E longitude above equator in a geostationary orbit. For a typical comparison of Equinoxes with Solistices, you may go through this link http://akmnscience.blogspot.in/2012/07/equinox-solstice-better-view.html Image Courtesy: Dundee Satellite Receiving Station http://www.sat.dundee.ac.uk/

Solar Eclipse (09 Mar 2016) is hardly visible over Tirupati. Here is an animated version (Figure (a)) of the simulation I have prepared using the free open source "Stellarium" software. The Sun rises over Tirupati by 06:23 IST. Meanwhile eclipse has already begun and being in penumbra region, it's partial eclipse over here. Click here to see the eclipse For reference, the figure (b) of eclipse locations are shown in the figure below (scroll down) which also shows time in Tirupati during the events.  (courtesy: timeanddate.com ) Figure (a): Animation of the solar eclipse (simulated) over Tirupati. 'E' indicates East Figure (b): How eclipse happens world wide (courtesy: timeanddate.com)

I am sharing a few photos of Lightning I had clicked yesterday night over National Atmospheric Research Laboratory, Dept. of Space located at Gadanki, Andhra Pradesh, India. Cumulonimbus cloud band was observed in the eastern and southern sky and Gadanki was in periphery of the rain band. Also see the animated time series photos of the steps of lightning .  ~~~~~~~~~ Note the return stokes and bolts...!! ~~~~~~~~~ Recommended viewing: Full screen. Thanks to my Asus Zenfone.

Concentrations of the greenhouse gas carbon dioxide (CO2) in the global atmosphere has surpassed 400 ppm  for the first time in human history in April. As on May 03, 2014 the value is still higher 401.80 ppm. Read more from official website http://keelingcurve.ucsd.edu/ Here is the screen shot. Courtesy: Scripps Institute of Oceanography http://keelingcurve.ucsd.edu/

Satellite images are are rich with useful and interesting information. It is not difficult to interpret them... here are some tips and stratergies....    They can show us how much a city has changed, how well our crops are growing, where a fire is burning, or when a storm is coming.  Here is a practical approach as given by Nasa Earth Observatory. Look for a scale Look for patterns, shapes, and textures Define the colors (including shadows) Find north Consider your prior knowledge Read more.... Check this link..... http://earthobservatory.nasa.gov/Features/ColorImage/?src=eorss-features Courtesy: Nasa Earth Observatory

Every year during winter time (Aug-Sep) , extend of Antarctic sea ice  increases. But this year...... it has reached record largest extend.... Reports NASA. Interesting .....!  Isn't it....? Read the following graph to compare the changes in sea ice extend. Read More: Antarctic Sea Ice Reaches New Maximum Extent Why should it grow....? It's an interesting field of research....! There are few hypothesis... Read More http://theconversation.com/why-is-antarctic-sea-ice-growing-19605  Courtesy: NASA earth observatory

Temperature data from four international science institutions. All show rapid warming in the past few decades and that the last decade has been the warmest on record. Courtesy:Nasa Global CLimate change http://climate.nasa.gov/scientific-consensus

High El Nino -Southern Oscillation (ENSO) activity in the late 20th century is a footprint of global warming says a recent study. An international team of scientists spearheaded by Jinbao Li and Shang-Ping Xie, while working at the International Pacific Research Center, University of Hawaii at Manoa, has compiled 2,222 tree-ring chronologies of the past seven centuries from both the tropics and mid-latitudes in both hemispheres. Their work is published in the June 30, 2013 online issue of Nature Climate Change . Li, J., S.-P. Xie, E. R. Cook, M. Morales, D. Christie, N. Johnson, F. Chen, R. D'Arrigo, A. Fowler, X. Gou, and K. Fang (2013): El Niño modulations over the past seven centuries. Nature Climate Change . http://dx.doi.org/10.1038/nclimate1936 Caption: This graph shows El Niño variability derived from tree rings (blue) and instrumental measurements (red). The dashed lines indicate boundary for natural variability. Recent El Niño behavior is largely beyo...

Global warming from greenhouse gases affects rainfall patterns in the world differently than that from solar heating, according to a study. The scientists, led by Jian Liu (Chinese Academy of Sciences) and Bin Wang (International Pacific Research Center, University of Hawaii at Manoa), showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then. As a result of global warming, precipitation is likely to increase in high latitudes and the tropics and to decrease in already dry subtropical regions. Read More http://phys.org/news/2013-01-greenhouse-gases-solar-complexity-global.html http://www.nature.com/nature/journal/v493/n7434/full/nature11784.html doi:10.1038/nature11784

2012 was the ninth warmest year since 1880. The map at the top depicts temperature anomalies, or changes, by region in 2012; it does not show absolute temperature. Reds and blues show how much warmer or cooler each area was in 2012 compared to an averaged base period from 1951–1980. For more explanation of how the analysis works, read  World of Change: Global Temperatures. The average temperature in 2012 was about 14.6 degrees Celsius (58.3 degrees Fahrenheit), which is 0.55°C (1.0°F) warmer than the mid-20th century base period. The average global temperature has increased 0.8°C (1.4°F) since 1880, and most of that change has occurred in the past four decades. Read more:  http://earthobservatory.nasa.gov/IOTD/view.php?id=80167&src=eoa-iotd

Greenland is an immense, glittering expanse of snow and ice. But in recent summers, satellites have been observing less “glitter” from the Northern Hemisphere’s largest ice expanse due to surface melt and other changes caused by warmer temperatures. The summer of 2012 found Greenland darker than it has been since ice-sheet-wide observations began in 2000. The darkest areas occurred around the perimeter of the island—the lowest elevations, where melting is most significant—but virtually the entire ice sheet showed below-average reflectivity. Courtesy: Climate Watch Magazine by NOAA http://www.climatewatch.noaa.gov/article/2012/less-glitter-greenland-ice-sheet-continued-to-darken-in-summer-2012 Map by NOAA Climate.gov team, based on NASA MODIS albedo data provided by Jason Box, The Ohio State University. Inset image is from NASA’s Terra satellite, courtesy the  LANCE MODIS Rapid Response Project.  Reviewed by Jason Box.

Climate model projections that show a greater rise in global temperature are likely to prove more accurate than those showing a lesser rise. The study was published in the journal - Science. National Center for Atmospheric Research scientists John Fasullo and Kevin Trenberth analyzed how well 16 leading sophisticated climate models reproduce observed relative humidity in Earth's tropics and subtropics. They used observations from two NASA satellite instruments - the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft and the Clouds and Earth's Radiant Energy System (CERES) . Climate model projections showing a greater rise in global temperature are likely to prove more accurate than those showing a lesser rise, according to them. Read in detail:  https://www2.ucar.edu/atmosnews/news/8264/future-warming-likely-be-high-side-climate-projections-analysis-finds http://www.nasa.gov/topics/earth/features/earth20121108.html

Have you heard of Cirrus cloud descending .........? What is it ......? Is it a frequent phenomenon .....? Does it have seasonal dependence ....? Where does it occur ......? Why do cirrus descend .....? What is it's impact .......? We have discovered the phenomenon using 3 years of lidar observations over Thiruvananthapuram, near southern tip of India that Cirrus clouds frequently DESCEND.....! After analysing the data together with other observations and models, we have come up answers to the above questions.  The observations and results are now accepted by the scientific community and it finds a place in the Journal of Geophysical Research - JGR (Atmosphere). Read more... Here is the link:  http://www.agu.org/pubs/crossref/2012/2011JD017406.shtml   Nair, A. K. M. , K. Rajeev, M. K. Mishra, B. V. Thampi, and K. Parameswaran  ( 2012 ),  Multiyear lidar observations of the descending nature of tropical cirrus clouds ,...