Himawari Image Navigation and Registration (INR) Monitoring Guide

Computation methods

The accuracy of Himawari Standard Data (HSD) projection is evaluated by comparing coastlines in Himawari imagery with those on referential maps. This evaluation is known as landmark analysis.

Landmark analysis vectors representing positional errors between images and reference maps are determined via phase-only correlation, with those appearing contaminated by cloud and statistical outlier vectors removed. Rotational misalignment is not taken into account. Analysis involves imagery from Himawari Band 13 (10.4 µm) and band 7 (3.9 µm, and is performed after every full-disk observation.

Error vectors computed from landmark analysis contain both image registration errors and landmark analysis errors. As the latter can be assumed to have no bias, the error vector average is taken to represent the most likely image registration error.

Band-to-band co-registration analysis is a result of evaluation to determine the relative misalignment between HSD sensor bands. This is done via pattern matching, as in landmark analysis, but also involves comparison of coastlines and cloud patterns in target band imagery with those in referential band imagery rather than on referential maps. The technique is referred to here as co-registration analysis.

Band 13 imagery (10.4 µm) is utilized for reference in this analysis, which is conducted after hourly observation.

How to Read the Charts

Himawari Standard Data image landmark analysis map

This page shows horizontal mapping of HSD location error vectors evaluated from landmark analysis. Imagery dates and times can be selected from the menu on the left. Error vectors are highlighted, and the horizontal/vertical vectors in the bottom left are references for error vectors representing a single infrared pixel length. These maps are posted around 10 minutes after each observation on a real-time basis.

Time sequence of Himawari Standard Data image landmark analysis

This page shows temporal trends and changes in HSD navigation accuracy for Band 13. The charts on the monitoring page show temporal sequences of error vector components, vertical length, horizontal length, magnitude and direction. Also shown are average landmark analysis error vectors with respect to four regions for each image.

Himawari Standard Data Co-registration analysis map

This page shows horizontal mapping of HSD band-to-band registration error vectors evaluated via co-registration, with data indicating net positional errors with respect to reference Band 13 imagery. All band results except those from the reference band are selectable. Error vectors displayed on maps on the right and lines in the bottom left are identical to those of landmark results, as is the date/time selection menu on the left.

Time sequence of Himawari Standard Data Co-registration analysis

This page shows temporal trends and changes in HSD co-registration accuracy for the target band (except for Band 13). While the charts here show similar landmark content, the error plots show average co-registration error vectors for the whole full-disk area. The selection menu on the left indicates the 15 target bands rather than landmark regions.

Reference