The atmospheric continuum in the “terahertz gap” region (15–700 cm−1): Review of experiments at SOLEIL synchrotron and modeling

The water vapor self-continuum in the “terahertz gap” region (15–700 cm−1): Experiment versus MT_CKD-3.5 model

“…Recently published review of experimental studies of atmospheric continuum in the region 15-700 cm −1 [1], hereafter referred to as Paper I, includes a comparison of experimental data on water vapor self-continuum cross-section (Fig. 1), its temperature exponent (Fig.…”

“…Figure 1 also demonstrates that the variation of the continuum value due to the "pedestal" below the resonance lines (which is originated from the procedure of cutting off the line wings and attributed to the continuum in the MT_CKD, but is preserved to the resonance absorption in our studies) is smaller than the spread of experimental points. The temperature exponent of the MT_CKD-3.5 model was determined similarly to [1,4], particularly, on the basis of Eq. ( 5) of [4] and continuum cross-sections calculated using version 3.5 (instead of 3.2 used in [1,4]) at 296 K and 326 K. Obtained temperature exponent demonstrates good qualitative agreement with experimental data [4,5,7,[11][12][13]15,16], however, a slight overestimation is still notable (Fig.…”

“…The temperature exponent of the MT_CKD-3.5 model was determined similarly to [1,4], particularly, on the basis of Eq. ( 5) of [4] and continuum cross-sections calculated using version 3.5 (instead of 3.2 used in [1,4]) at 296 K and 326 K. Obtained temperature exponent demonstrates good qualitative agreement with experimental data [4,5,7,[11][12][13]15,16], however, a slight overestimation is still notable (Fig. 2).…”

“…3 of Paper I). Self-continuum temperature exponent: grey empty circles (SOLEIL measurements) [4], black triangles [7,11], grey squares [12], black star: [13], grey empty squares [16], black circles [15], black inverted triangles [5], red solid curve (continuum model obtained as a sum of true bound metastable dimers, and far-wings contributions simulated by in [1]), green dash curve (stable dimer) [19], orange solid curve (metastable dimer model), blue dash-dot curve (far wings model), green curve (MT_CKD-3.2 model) [2], and black solid curve (MT_CKD-3.5 model) [2]. [9,10], black empty triangles [11], grey squares [12], grey curve [18], grey empty squares [16], grey filled circles [15], grey star [17], green dash curve (stable dimer model), orange solid curve (metastable dimer model), blue dash-dot curve (far wings), red solid curve (continuum model obtained as a sum of true bound metastable dimers, and far-wings contributions simulated by in [1]), green curve (MT_CKD-3.2 model) [2], and black thin curve (MT_CKD-3.5 model).…”

“…3 (analogue of Fig.4 of Paper I). Continuum spectral function: grey empty circles(SOLEIL measurements)[9,10], black empty triangles[11], grey squares[12], grey curve[18], grey empty squares[16], grey filled circles[15], grey star[17], green dash curve (stable dimer model), orange solid curve (metastable dimer model), blue dash-dot curve (far wings), red solid curve (continuum model obtained as a sum of true bound metastable dimers, and far-wings contributions simulated by in[1]), green curve (MT_CKD-3.2 model)[2], and black thin curve (MT_CKD-3.5 model).…”