Remove["Global`*"];
Timing[
frq = 1;
shuki = 1/frq;
r[x_, y_, x0_, y0_] := 
            Sqrt[(x - x0)^2  +  (y - y0)^2];
warur[x_, y_, x0_, y0_] := 
            If[Sqrt[(x - x0)^2  +  (y - y0)^2] == 0, 
              1, (1 - 
                    Exp[-Sqrt[(x - x0)^2  +  (y - y0)^2]])/
                Sqrt[(x - x0)^2  +  (y - y0)^2]];

velo = 4;
hachou = velo/frq;

keika = 20;
bunkatu = 200;
kankaku = keika/bunkatu;
naminokazu = 10;

t0list = 
            Table[kankaku*(i - 1), {i, bunkatu + 1}];
kaishilist = 
            Table[keika/naminokazu*(i - 1), {i, naminokazu}];

nagasa = 100;
kizami = 80;
dl = nagasa/kizami;

snaplist = Table[Null, {i, bunkatu + 1}];
gsnaplist = 
            Table[Null, {i, bunkatu + 1}];

nami[t_, x_, y_, x0_, y0_] := 
            If[(velo*(t - shuki) < 
                    r[x, y, x0, y0])  &&  (r[x, y, x0, y0] < velo*t), 
              Sin[-2*
                    Pi*(r[x, y, x0, y0] - velo*(t - shuki))/hachou]*
                warur[x, y, x0, y0], 0];
x0 = -30;
y0 = 0;



Do[
ima = t0list[[k]];
amplist = 
                  Table[0, {i, kizami + 1}, {j, kizami + 1}];

Do[
If[
                      kaishilist[[j]] < ima, 
cx = 
                        x0 + 0.5*velo*
                            kaishilist[[j]]; 
cy = 
                        y0; 
t = 
                        ima - kaishilist[[j]]; 
tmplist = Table[N[nami[t, dl*(i - (kizami/2)), dl*(j - (kizami/2)), 
                              cx, cy]], {i, 0, kizami}, {j, 0, 
                            kizami}]; 

amplist = amplist + tmplist, 
                      Continue[]];
, {j, naminokazu}];
snaplist[[k]] = 
                  Transpose[amplist];
Print[" k = "; k];
gsnaplist[[k]]=ListPlot3D[snaplist[[k]], 
                    PlotRange -> {-1, 1}, Mesh -> False, 
                    Boxed -> False, Axes -> False (*, DisplayFunction -> Identity  *)];
,{k, bunkatu + 1}];

  

snaplist  >> "test_doppler.txt";
Export["test_doppler.avi", 
            gsnaplist, "AVI"];
]

Null