In the present study, we investigate two-point statistics of fluctuating streamwise wall shear stress τx and wall heat flux qw by exploiting a direct numerical simulation database of supersonic turbulent boundary layers over a heated wall and a cooled wall at the friction Reynolds number around 800. By separately investigating positive and negative families of τx and qw with the aid of the conditional correlation analysis, we identify the asymmetrical deformation of τx and qw, reminiscent of and ascribed to the asymmetrical deformations of sweeps and ejections events. The degree of such asymmetry is alleviated by the lower wall temperature. The spatial orientation of τx is insensitive to the wall temperature, whereas the spanwise elongated qw that is closely related to the wall pressure is manifested merely in the cooled-wall case. The cross correlation between τx and the fluctuating streamwise velocity u′ reveals that low-speed streaks related to negative τx are more inclined to the wall than high-speed ones related to positive τx by 4°5°, and that the phase lag between negative τx and u′ is larger than that between positive τx and u′ except in the near-wall region. Such a difference is proportional to the wall distance and should be considered for models predicting near-wall and wall quantities using signals in the logarithmic layer.

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