# FORCE--Landsat + Sentinel-2 Analysis Ready Data and Beyond
## 3 Processing Capability
### Level 2: Analysis Ready Data
#### 3.2.3 Output Format  
The gridded data are provided as compressed GeoTiff or flat binary format, accompanied by metadata. For each dataset, multiple products are stored as different files. Bottom-of-Atmosphere (BOA) reflectance (multi-band, same resolution) and quality assurance information (QAI; single band) are standard output. To homogenize and simplify usage of multi-sensor data, original band names are not carried to Level 2. Instead, specific bands can be addressed using their wavelength designation in the higher-level FORCE routines (see Table 1). The QAI product collects a number of quality-relevant status flags in bit notation (Table 2).  
Figure 5: Data cube of Landsat 7/8 and Sentinel-2 A/B Level 2 ARD for Southeast Berlin, Germany. A two-month period of true color image chips for one \(30\times 30\) km tile is shown.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Bit No.** & **Parameter Name** &
\begin{tabular}{c} **Bit** \\ **Comb.** \\ \end{tabular} & **Integer** & \multicolumn{1}{c}{**State**} \\ \hline
0 & Valid data & 0 & 0 & valid \\  & 1 & 1 & no data \\ \hline  & & 00 & 0 & clear \\
1-2 & Cloud state & 01 & 1 & less confident cloud (i.e., buffered cloud 300 m) \\  & & 10 & 2 & confident, opaque cloud \\  & & 11 & 3 & cirrus \\ \hline
3 & Cloud shadow flag & 0 & 0 & no \\  & & 1 & 1 & yes \\ \hline
4 & Snow flag & 0 & 0 & no \\  & & 1 & 1 & yes \\ \hline
5 & Water flag & 0 & 0 & no \\  & & 1 & 1 & yes \\ \hline  & & 00 & 0 & estimated (best quality) \\
6-7 & Aerosol state & 01 & 1 & interpolated (mid quality) \\  & & 10 & 2 & high (aerosol optical depth \(>\) 0.6, use with caution) \\  & & 11 & 3 & fill (global fallback, low quality) \\ \hline
8 & Subzero flag & 0 & 0 & no \\  & & 1 & 1 & yes (use with caution) \\ \hline
9 & Saturation flag & 0 & 0 & no \\  & & 1 & 1 & yes (use with caution) \\ \hline
10 &
\begin{tabular}{c} High sun zenith \\ flag \\ \end{tabular} & 0 & 0 & no \\  & 00 & 0 & top. correction \\
11–12 & Illumination state & 01 & 1 & medium (incidence angle \(<\) 55\({}^{\circ}\)–80\({}^{\circ}\), good quality \\  & & 01 & 1 & for top. correction) \\  & & 10 & 2 & poor (incidence angle \(>\) 80\({}^{\circ}\), low quality for top. correction) \\  & & 11 & 3 & shadow (incidence angle \(>\) 90\({}^{\circ}\), no top. correction applied) \\ \hline
13 & Slope flag & 0 & 0 & no (cosine correction applied) \\  & & 1 & 1 & yes (enhanced C-correction applied) \\ \hline
14 & Water vapor flag & 0 & 0 & measured (best quality, only Sentinel-2) \\  & & 1 & 1 & fill (scene average, only Sentinel-2) \\ \hline
15 & Empty & 0 & 0 & TBD \\ \hline \hline \end{tabular}
\end{table}
Table 2: Quality assurance information (QAI) description.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Wavelength** & \begin{tabular}{c} **FORCE Level** \\ **2 Band** \\ **LND0 [4–8]** \\ \end{tabular} & \begin{tabular}{c} **FORCE Level** \\ **2 Band** \\ **SEN2[AB]** \\ \end{tabular} & \begin{tabular}{c} **USGS Level 1** \\ **Band** \\ **Landsat 4/5/7** \\ \end{tabular} & \begin{tabular}{c} **USGS Level 1** \\ **Band** \\ **Landsat 4/5/7** \\ \end{tabular} & \
\begin{tabular}{c} **USGS Level 1** \\ **Band** \\ **Landsat 8** \\ \end{tabular} &
\begin{tabular}{c} **ESA Level 1** \\ **Band** \\ **Sentinel-2 A/B** \\ \end{tabular} \\ \hline BLUE & 1 & 1 & 1 & 2 & 2 \\ GREEN & 2 & 2 & 2 & 3 & 3 \\ RED & 3 & 3 & 4 & 4 \\ REDEDGE1 & - & 4 & - & - & 5 \\ REDEDGE2 & - & 5 & - & - & 6 \\ REDEDGE3 & - & 6 & - & - & 7 \\ BROADNIR & - & 7 & - & - & 8 \\ NIR & 4 & 8 & 4 & 5 & 8A \\ SWIR1 & 5 & 9 & 5 & 6 & 11 \\ SWIR2 & 6 & 10 & 7 & 7 & 12 \\ \hline \hline \end{tabular} _Note:_ Level 1 bands, which are mainly intended for atmospheric characterization are used internally, but are not output.  
\end{table}
Table 1: Level 2 output bands and mapping to original Level 1 bands.