%0 Journal Article %T Quasi-geostrophic type equations with weak initial data %A Jiahong Wu %J Electronic Journal of Differential Equations %D 1998 %I Texas State University %X We study the initial value problem for the quasi-geostrophic type equations $$ displaylines{ {partial heta over partial t}+ucdotablaheta + (-Delta)^{lambda}heta=0,quad hbox{on } {Bbb R}^nimes (0,infty), cr heta(x,0)=heta_0(x), quad xin {Bbb R}^n,, cr} $$ where $lambda$, ($0leq lambda leq 1$) is a fixed parameter and $u=(u_j)$ is divergence free and determined from $heta$ through the Riesz transform $u_j=pm {cal R}_{pi(j)}heta$, with $pi(j)$ a permutation of $1,2,cdots,n$. The initial data $heta_0$ is taken in the Sobolev space $dot{L}_{r,p}$ with negative indices. We prove local well-posedness when $$ {1 over2} Keywords Quasi-geostrophic equations --- Weak data --- Well-posedness. %K Quasi-geostrophic equations %K Weak data %K Well-posedness. %U http://ejde.math.txstate.edu/Volumes/1998/16/abstr.html