# The CYGNSS Mission: On-Going Science Team Investigations
## 2 Methodology, Results, and Discussions
### Data Products
CYGNSS raw Intermediate Frequency (IF) data processing at Institute of Space Sciences (ICE)--Institute of Space Studies of Catalonia (IEEC) demonstrated potential applications over land, inland water bodies, and in extreme events (e.g., hurricanes and floods) and regions of great geophysical interest (e.g., Himalayan glaciers). Finally, variational wind speed retrievals of uncalibrated CYGNSS data demonstrated a better response to high winds than the Advanced SCATterometer (ASCAT) radars and similar response as the Soil Moisture Ocean Salinity (SMOS) mission (Figure 3). Figure 2: Data processing flow of the CYGNSS data products [19]. Session 2: Data Products II  
A CYGNSS L1 land product was developed by the University Corporation for Atmospheric Research (UCAR). This L1 land product [23] contains variables also found in the L1 ocean product, such as position, velocity, time, attitude, and antenna gain, while eliminates variables that were only applicable to ocean applications. The sandbox version of this product is available to all the Science Team members and includes almost all land bodies observed within CYGNSS coverage and a 50 km \"skirt\" of the ocean; however, very high-altitude regions, such as the Tibetan Plateau are not available due to on-board open loop tracker limitations. In order to better assist with the CYGNSS wind speed product, several institutions including the National Oceanic and Atmospheric Administration (NOAA) have developed CYGNSS L2 wind speed products, which have been released through the PODAAC. As  
Figure 3: Sentinel-1A and -1B wind retrievals for Typhoon “Trami”, acquired on Sep 28 9:35 (lower) and Sep 29 9:27 (upper) 2018, approximately 24 h apart (from [[https://cyclobs.ifremer.fr](https://cyclobs.ifremer.fr)]([https://cyclobs.ifremer.fr](https://cyclobs.ifremer.fr)), 3 April 2021). The colored tracks are CYGNSS passes ~8 h before the first Synthetic Aperture Radar (SAR) wind field image (Sep 28, between 00:50 and 01:26) when the eye was further South. The CYGNSS wind retrievals for each of the tracks, estimated by [PERSON] et al. [22], are shown in black dots (“Est” legend) in the panels surrounding the images. The red dots are for European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-5 wind speeds interpolated to the CYGNSS tracks, and Advanced SCATerometer ASCAT-A/B are shown in blue circles when co-located. compared to the original CYGNSS L2 wind speed product, the NOAA version is gridded into 25 \(\times\) 25 km grid cells, and it uses a custom Geophysical Model Function (GMF) with a track-wise debiasing algorithm. At the time of this meeting, the presenters highlighted some of the minor changes going into v1.1 of the product, such as, e.g., resolving an issue with the star tracker flag, which led to an 18% increase in daily data on some dates. Most importantly, v1.1 of the CYGNSS-NOAA winds have led to improvements in wind speed retrievals within the cores of TCs. This product (Figure 4) was released through the PODAAC during the last fall, with data availability from March 2017 through the present [24]. An ocean surface heat flux product was released in August 2019, which combines CYGNSS L2 winds with reanalysis data from Modern-Era Retrospective analysis for Research and Applications (MERRA-2) in order to estimate the latent and sensible heat fluxes at each CYGNSS specular point [25]. An update of L2 CDR v1.0 of the CYGNSS ocean surface heat flux product was released in October 2020. As compared to the original version (Science Data Record (SDR) v1.0), the latest version of this product uses the CDR v1.0 L2 winds from CYGNSS, leading to a slightly improved performance as compared to buoy data and improved data availability for the Fully Developed Seas (FDS) versions of these products. Additionally, MERRA-2 variables are now matched in time and space to CYGNSS specular points using a tri-linear interpolation method rather than nearest neighbor, which has removed some biases and fixed issues near land.