A first intercomparison of JNO2 measurements by actinic flux spectroradiometry (SR) and chemical actinometry (CA) was performed in summer 1997 in J¿lich, Germany. During this experiment (JCOM97) a large set of data was collected with a time resolution of ~1 min, showing a high linear correlation (R=0.998) in JNO2. Linear regression indicates a good absolute agreement with the CA being 6% higher than SR if the quantum yield recommended by NASA/JPL (1997) and recently published data of the NO2 absorption spectrum (&sgr;NO2) is used for the evaluation of the SR-data. The influence of using previously published &sgr;NO2 data is discussed. Overall the comparison suggests that JNO2 can be measured by either CA or SR with an accuracy of better than 10%. ¿ 2000 American Geophysical Union