Archive for category high-speed camera observations
Citizen Science – the collection and analysis of data relating to the natural world by members of the general public, typically as part of a collaborative project with professional scientists.
This aspect of scientific research and understanding is rapidly growing primarily due to increased technology advancement, smartphone integration and interest by the general public. Smart phones and associated apps can now collect valuable data quickly and easily. I use my smartphone to collect data using the Globe Observer app and have made cloud observations from both polar regions and remote ocean locations. I also make weather observations using the mPing app.
The contributions can be significant as was evident with the aurora-related phenomenon now known as STEVE. Aurora chasers have recorded (and named STEVE) for quite awhile, but now their images and documentation combined with correlated scientific observations and analysis has lead to a better understanding of this phenomenon.
As a lightning research scientist, I am frequently approached with interesting lightning observations from the general public. These usually come in the form of video and digital still images. When I am able, I try to investigate these observations using what tools and analysis methods I have available, and often involve my willing colleagues that specialize in various aspects of lightning research. I encourage these observations as they have shown us things we often cannot necessarily capture in a confined research project domain or timeframe. Many of the images and video come from storm chasers and weather spotters.
Our biggest challenge when analyzing these data is correlating them to a specific time and place so they can be compared with any other research data that might be available. There are now multiple lightning location networks operational as well as research lightning mapping arrays that continuously record lightning related data.
So what can you as a storm chaser or storm spotter do to contribute to citizen science? I have a few suggestions that will greatly increase the value and usability of your video and image recordings for scientific analysis.
- Time is incredibly important for lightning analysis especially when we are discussing events that typically last less than a second. Having the correct time set to within a couple of seconds on your cameras is very helpful if not essential for analysis. I set my camera time every time I format my sd card after downloading any images. I use the NavClock app but typically the mobile carrier time on your smartphone is accurate to within a few seconds so just using your phone time is good enough. I also set all my cameras to GMT which is the standard for data collection and analysis. It makes it easy when you don’t have to convert from the timezone where the image or video was captured.
- Location is the next important information needed for analysis. Some cameras have built in GPS that will record position to metadata (exif) as well as set the camera time accurately. I wish this was a standard feature on every camera, but unfortunately it is not. I use the app Geotag Photos Pro to capture and add position information to my images and video. The direction the camera was pointed is useful as well, but that parameter is more difficult to record as metadata. I believe Canon has an external GPS encoder that can provide heading information as well.
- Thankfully, digital cameras record extensive metadata that describes the parameters set when images are captured. These data are critical for photogrammetry analysis (e.g., sensor size, focal length, exposure time). Always keep the exif data and export it with the image when providing it for analysis. The metadata is embedded in jpg and dng file formats, but will be in a separate xmp sidecar file for native raw camera formats.
- The more data the better and the RAW camera format provides the maximum amount of data when capturing digital still images. I recommend always shooting in the RAW format.
As far as getting your observations to the scientific community, the Science Operations Officer at National Weather Service forecast offices is a great place to start. Twitter is also good for connecting with researchers.
Again, the importance of Citizen Science cannot be overstated. It is integral part of scientific exploration and understanding, and I encourage all to participate when and how they can. Besides its fun too.
Over the past six years my research colleagues and I have filmed lightning using high-speed digital cameras. In total we have captured 776 naturally occurring lightning flashes with recording speeds as high as 100,000 images per second. 158 of these flashes were cloud flashes in which some of the lightning leaders propagated outside of the clouds. 372 of theses flashes were negative cloud-to-ground flashes (-CG) and 206 were positive cloud-to-ground flashes (+CG). 41 of the flashes were upward flashes originating from tall towers in Rapid City.
During this last summer, we pursued a storm into the Badlands of South Dakota. The Badlands are a beautiful area of erosion in the plains creating incredibly photogenic landscapes, and it is personally one of my favorite places to photograph lightning. On this particular day, I was filming from the Pinnacles Overlook looking east across a road. I filmed a number of flashes, but during one instance I not only captured a +CG flash, I also captured a rare wild tourist roaming the South Dakota plains. Because I film from a highly modified truck with cameras and gadgets sticking out of it, he was a bit curious by the appearance of my vehicle. However, he was clearly more interested in getting to the next viewpoint and quickly scurried off never to be seen again. Here is the video…
Below is a video on the creation of Lichtenberg figures. Interesting is the subsequent bright short discharges that continue to take place after the initial discharge. These seem similar in appearance to recoil leaders, which form on positive leaders branches that become cutoff from a main channel. Compare the two videos below.
YouTube video of Lichtenberg creation.
Upward lightning (upward positive leaders) from a tower filmed at 9,000 images per second.