Dataset 1  Dataset 2  Dataset 3  Dataset 4  
Source  MEXT Readings  MEXT (SPEEDI)  TEPCO  Pachube 
Data available  since 13.3.2011 or 15.3.2011 hourly averages 
since 1.1.2010 10 minute data 
since 14.4.2011 10 minute data 
since 22.3.2011 different sources with 10 minute data or hourly averages 
hourly averages  hourly averages  hourly averages  hourly averages  
Minimum value (V_{min}) and maximum value (V_{max}) from usual value band: "Usual value band means a range of the maximum and minimum value observed before the earthquake" [MEXT: e.g. pdf])  Minimum value (V_{min}) and maximum value (V_{max}) calculated with the data of the respective locations from 1.1.2010 to 10.3.2011 (from hourly averages)  no value band  no value band 
Dataset 1, Dataset 2, Dataset 3 and Dataset 4  
Accumulated dose rate = summation of hourly averages of absorbed dose rate Accumulation period: 13.3.2011 up to today 

❚ ❚  ❚Accumulation of original data Missing values: ❚Accumulation of interpolated data:
Missing values are approximated since original data of average absorbed dose rate is not available for every hour. Missing data points are computed by linear interpolation.
∅Missing data at the beginning of the period:
Missing values at the beginning of the accumulation period (13.3.) will be set to 0.
All data taken into account in the accumulation is shown in the graph ‘interpolated raw data’ (top left button above the graph).
In those cases the calculated accumulation values show below the actual accumulation values. Regarding the assessment of the timeline: Radiation releases during the initial hydrogen explosions. 
The red graph shows the accumulation of 0,114 μGy/h based on an estimated average for Japan of 1000 μGy per year (equates 0,114 μGy/h *24 hours * 365 days). The accumulation starts with the first available value of the data set after 13.3.2011 (see missing values above).  
The green graph shows the accumulation of V_{max}. The accumulation starts with the first available value of the data set after 13.3.2011 (see missing values above). 
< V_{max}  < 10 * V_{max}  < 100 * V_{max}  > 100 * V_{max} 