  We describe the meson-meson data for the ($IJ^{PC}=00^{++}$) wave at
$280\leq\sqrt s\leq 1900$ MeV in two approaches: (i) the K-matrix approach and
(ii) the dispersion relation D-matrix method. With a good description of low
energy data (at $280\leq\sqrt s\leq 900$ MeV) as well as the data of two-meson
transition amplitudes and antiproton-proton annihilation into three
pseudoscalar meson states (at $450\leq\sqrt s\leq 1950$ MeV) we have found the
positions of the resonance poles: (i) for the $\sigma$ meson pole: $M_\sigma =
(390\pm 35)-i(235\pm 50)$ MeV; (ii) two poles for the $f_0(980)$, on the second
sheet (under the $\pi\pi$ cut): $M_{I} = (1011\pm 5)-i(35\pm 5)$ MeV, and on
the third sheet (under the $\pi\pi$ and $K\bar K$ cuts), $M_{II} = (1035\pm
50)-i(460\pm 50)$ MeV; for the $f_0(1370)$ meson, $M= (1285\pm 30)-i(160\pm
20)$ MeV; for the $f_0(1500)$ meson, $M = (1488\pm 4)-i(53\pm 5)$ MeV; for the
$f_0(1790)$ meson, $M = (1775\pm 25)-i(140\pm 15)$ MeV and for the broad state
$f_0(1200-1600)$ $M=(1540\pm 120)-i(550\pm 70)$ MeV. Our estimation of the
scalar-isoscalar scattering length obtained under different parameterizations
and assumptions about the quality of low energy $\pi\pi$ scattering data is
$a^0_0=(0.215\pm 0.040)\mu^{-1}_\pi$. We also discuss the idea according to
which the $\sigma$-meson could be a remnant of the confinement singularity,
$1/s^2$, in a white channel.
