理查遜數(Richardson number,縮寫Ri)是因為物理學家路易斯·弗萊·理查德森(1881–1953)而命名的無因次量,是浮力項和流速剪應力項的比值: R i = buoyancy term flow shear term = g ρ ∂ ρ / ∂ z ( ∂ u / ∂ z ) 2 {\displaystyle
Populus purdomii Rehder Populus puschkinii R.I.Schröd. Populus pyrifolia Kirchner, 1898 Populus qamdoensis Z.Wang & S.L.Tung Populus qiongdaoensis T.Hong