To be able to precisely estimate discharges in un-gaged streams and reconstruct hydrological features in river systems, the temporal and spatial variations of at-a-station hydraulic geometry (AHG) and their impacting factors need to be detected. To this end, the Yalong River and Upper Jinsha River, which located in southeast Qinghai-Tibet Plateau, are selected as case study. This investigation explores quantitative data on the magnitude of spatial and temporal variations in AHGs over a period of 10 years for 38 mountain reaches with drainage areas ranging from 0.53 × 10³ to 259.18 × 10³ km². Effects of ice regime and drainage area on AHG were discussed and the stability of AHG was analyzed. 42.1% of the reaches have flow velocity exponents that are greater than the river width and flow depth exponents combined. No significant spatial variation tendency is observed for AHG exponents while significant temporal variations are reported. Larger fluctuations are found for AHG exponents in annual variations compared with those in inter-annual variations. Ice regimes significantly contribute to the seasonal changes of AHGs. The relative differences of AHG coefficients (a, c, k) and exponents (b, f, m) with and without ice vary between −49.4 to 80.8% and −70.1% to 22.6%, respectively. Compared with no ice regime, the reaches with border ice and slush ice run have smaller exponents m and Froude Number and larger coefficients c and exponents f. Besides, coefficients a and exponents m increase while coefficients k and exponents b decrease with the increase of drainage area. However, coefficients c and exponents f exhibit no tendency with drainage area changes. AHG stabilities increase with the increased stream order and drainage area. Results of this study can enrich the AHG database for mountain rivers and provide a preliminary understanding of ice effects on AHG variations.

为了能够精确估算未测量径流中的流量并重建河流系统中的水文特征，需要检测站内水力几何形状（AHG）的时空变化及其影响因素。为此，以青藏高原东南部的雅long江和金沙江上游为案例研究。这项调查探索了10年内38个山区的流域面积从0.53×10 ³到259.18×10 ³ km ^2的AHGs时空变化幅度的定量数据。。讨论了冰区和流域面积对AHG的影响，并分析了AHG的稳定性。42.1％的河段流速指数大于河流宽度和流速深度指数的总和。对于AHG指数，没有观察到明显的空间变化趋势，而报告了明显的时间变化。与年度间变化相比，发现年度变化中AHG指数的波动更大。冰层状况极大地促进了AHGs的季节性变化。AHG系数（a，c，k）和指数（b，f，m的相对差））（有和没有冰）分别在-49.4至80.8％和-70.1％至22.6％之间变化。与无冰区相比，有边界冰和融雪的河段的指数m和弗洛德数较小，系数c和指数f较大。此外，随着流域面积的增加，系数a和指数m增大，系数k和指数b减小。但是，系数c和指数f流域面积无变化趋势。随着流向和排水面积的增加，AHG的稳定性也会增加。这项研究的结果可以丰富山区河流的AHG数据库，并初步了解冰对AHG变化的影响。